SAP integration with Visual Studio 6

Hai Every One..

I am VC++ developer. I like to know how to integrate my VC++ applications or components with SAP solutions. I am very very new to SAP.

I don't know even the basics of SAP architecture. Please could you give some links where I can get some documents to read about SAP and It's architecture. I don't have SAP system. Is it possible to download SAP evaluation software.

I need some documents regarding integration of VC++ 6.0 with SAP solution.