Infopath's SharePoint list integration is not that good. Although you're able to define a SharePoint List as a Data Source, you can't filter the List Items on the server side. This means make-or-break, unacceptable for large lists! Furthermore, in browser enabled Infopath Forms you are not able to define filter criterias for Dopdowns and Repeated lists.
Fortunately there's another way to get List Items in your form and to filter them on the server side - The SharePoint RPC Protocol.
Proceed as follows:
- Start Infopath 2007 and create a new Form
- In the menu select "Extras" -> "Data Connections" (unfortunately I've got a German Infopath Edition, hope my translations will be suitable)
- Choose "New"
- Select "New Connection" -> "Receive Data"
- Choose "XML-Document"
- Enter the Path: "http://[server]/[site]/_vti_bin/owssvr.dll?Cmd=Display&List=[Guid]&View=[encoded GUI]" Instead of using a view, you could explicitly specify the filter criterias: "http://[server]/[site]/_vti_bin/owssvr.dll?Cmd=Display&List=[Guid]&XMLDATA=1&FilterField1=[Name]&FilterValue1=[Value]&FilterField2=..." (get the ids by browsing to the Settings Page of the View and make them out of the URL)
Now use the Data Source as usual. That's all.