As SharePoint gets more popular, we often face situations that we need to integrate multiple existing SharePoint instances or sometimes switch hardware with bigger capacity.  With these factors, it is unavoidable to touch configuration database or administrator/owners of up-and-running WSS or MOSS sites.  Here's a quick summary of which areas need to be re-configured so you can, at least, have various names of areas that you need to dive deeper for next steps.

 1. Administrator account change.

- Application Pool Identity.

This can be found in Property of the Application Pool where WSS is running upon.  First open up IIS and expand Application Pool branch to locate this.

- SQL Server Roles

The new administrator account should have the following two SQL Server Roles in order to make WSS run.  Obviously DbCreator role to enable WSS to create a new database instance in SQL Server for a new application that is created from within SharePoint.  Granting these two server roles does not necessarily means the account can have admin/similar access to other databases where granular access control is important because only with these two roles there are not many things the account can do to other databases that are owned by other account.

DbCreator

SecurityAdmin

- Local server user groups

The new administrator account should be part of several local user groups.  The minimum required groups are in the below but you can check all other groups if there's any local user groups where previous account belonged to.

IIS_WPG

STS_WPG

- Misc.

If required, administrator for Top-level Site collection through SharePoint Central administration, or in .NET configuration related files such as Web.config / Machine.config if any exist.

Needless to say you need to reset the environment once all those steps above are done.   But when doing this, rather than doing bigger(?) scaled reset such as Server restart, starting from smaller scaled reset would be considered always better practice.

You can first restart only Application Pool or only the web site, then reset IIS, the finally restart server if still need to refresh/reset your changes.

2. SharePoint database relocation.

There are three major categories of database to consider.  One Configuration database per WSS instance, One Central administration content databse per WSS instance and multiple databases per SharePoint application.  You can consider Central administration database is simply another content databse.  Having said that you will use different tools for Configuration database and Content database(whether central admin or not) respectively.

- SharePoint Configuration database

The name of the database is typically "SharePoint_Config" as default one by WSS but could be something else.  This name can be found from Central administration > Operation > Topology and Services > Servers in Farm > Click the link of "Windows SharePoint service database".  You cannot see the name under "Configurable" View because it is not configurable via Central administration.

As said the change to this area is not possible in individual application level because when Central administration is launched, already configuration database is loaded.  You can use either of the following methods. 

Using SharePoint Configuration Wizard

you might have used this tool when installing WSS/MOSS but this tool can be again used.  It is one of two tools installed by WSS under Administrative Tools of Server.  The other one is so-popular Central Administration Tool.

You will need extreme caution when using this tool.  Sometimes you may need to use SharePoint Setup utility from "Add or remove Programs" panel.

When using configuration wizard, you should run the tool twice.  First time to disconnect current server from configuration database, and second time to reconnect to the new database.

Using STSADM tool

You can use SharePoint provided STSADM script.  See the syntax below.  Maybe if you need batch type script including changing configuration database, you may want to use this.

stsadm.exe -o setconfigdb -connect -ds Server1 -dn Server1_collab -du User1 -dp password

- Content database

There could be multiple databases  one for each SharePoint application including Central administration application.  You need to change for each application.

First change Default database server where new application database will be created.  You can find this from Central administration > Operation > Data Configuration > Default Database Server.

And then, change content database for each application using the menu Central administration > Application Management > SharePoint web application management > Content database.  One important thing is you need to first remove any content database and then add the new databases using the link provided.  BTW i'm assuming the new databases is a copy of the existing content database so it should have "content" of course.

One thing to note is about Central Administrationsite.  Even though it is one of SharePoint sites, it has control over configuration information for all SharePoint application level and below, better off to change other content databases first.  Once all other content databases are done converted to new ones, then Central administration can be handled using command line utility STSADM as follows:

Stsadm.exe -o addcontentdb -url <Central admin site url such as http://training:21470> -databasename <Central admin content database name such as SharePoint_AdminContent2> -databaseserver <DB server name>

Or

Try PSConfig.exe utility as suggested in http://www.eggheadcafe.com/software/aspnet/28587849/sharepointadmincontent-d.aspx.  This however will touch Configuration database and create a "new" content databse for Central administration site - I didn't try this so not sure what details are there to note though.

- PSConfig.exe - simply because Central administration site will not be available any more once you remove existing database.  For more information on using PSConfig.exe refer to http://technet2.microsoft.com/Office/en-us/library/a59c4e8f-9b7f-4127-8199-1b9ab76991501033.mspx?mfr=true.

Needless to say backups will be required before you make any actual changes.  Hope this article provided you one-stop information for your WSS relocation job !!!