As its name suggests, Forms Server 2007 is one of Microsoft's server products that allows business and IT to deliver visually appealing electronic email/web/mobile forms and use these forms as a information gathering tool. It can save hours of ASPNET Form development time. When you couple this with SharePoint - you get a powerful way to gather information, drive InfoPath Forms as form web pages within SharePoint, deliver Content Types based on InfoPath Forms and apply workflow instances or use them for workflows.
If you're starting out with Forms Server and SharePoint, take a look at this link and download the file:
http://www.microsoft.com/downloads/details.aspx?familyid=B3169275-C9FD-4871-B0D9-3C0BAB319ED5&displaylang=en
Over n Out
MarcL