Yes, this is possible. You can manipulate SharePoint's list metadata from inside InfoPath. You must have InfoPath toolkit installed. See following post for reference:

http://www.sharepointblogs.com/ssa/archive/2006/06/02/8029.aspx

You can get/set values in SharePoint list. Recently, I was working on a workflow solution that involved both SharePoint and InfoPath. Till now, all the workflow solutions that I developed used SharePoint as the main tool and workflow was built into SharePoint but this time, the requirement was a bit different. We wanted to build the workflow solution directly in InfoPath form and part of this requirement was to set a property's value in document library directly from InfoPath form. "Approval Status" field in form library can contain one of the following values:

1. Approved
2. Rejected
3. Pending

Depending on your form's requirements, you can set the value of "Approval Status" field directly from InfoPath. Here is the code:

SPWeb mySite = new SPSite("http://yourportal/sites/HR/HRForms/Forms/mod-view.aspx").OpenWeb();
SPFolder myFolder = mySite.GetFolder("HRForms");
SPFileCollection myFiles = myFolder.Files;
try
{
foreach (SPFile fyle in myFiles)
{
fyle.Item.ModerationInformation.Status = Microsoft.SharePoint.SPModerationStatusType.Pending;
fyle.Item.Update();
}
}


Code Explanation:

Open your site using OpenWeb() method. In the code above, first line opens a site called "HR". "HR" site has a folder named "HRForms" and this folder contains all forms. In the for-each loop, we are setting each file's status to "Pending". It is important to call the Update() method in order to apply the changes.

Add a reference to Microsoft.SharePoint (Microsoft.SharePoint.dll) and add following namespaces in the code:

using Microsoft.SharePoint;
using System.Collections;

-SSA