InfoPath Dev

Hi,  I am new to InfoPath, and Need to create a WCF for InfoPath in order to read data form SQL and AD in the InfoPath form, and then publish it on SharePoint. I am still using SharePoint 2007. If you could refer me to some helpful documents that will be create. Thanks,   

Thanks for your help Patrick. I am assuming that WCF would work too, right? I am using SharePoint and InfoPath 2007. Could I use Visual Studio 2008? Or should it be 2005?

Is there any other option besides InfoPath to do forms and workflows with SharePoint?

Hi, I am new to InfoPath. Trying to create a form. Need the form to connect both to SQL and AD. Based on the username entered, should put some info + Employee Number form SQL. After that based on the Employee Number populate rest of the fields form AD. How do I do this? Thanks,