Programming

ABAP Hints and Tips
For ABAP/4 programmers to find hints and tips on programming with SAP's ABAP, useful function modules, and source code.
http://abap4.tripod.com/

CT-Software
Searchable ABAP Freeware Pool
http://www.ct-software.com/reportpool_frame.htm

SAP Development
Provides ABAP source code and information on SAP's technologies.
http://www.sapdevelopment.co.uk

SAP-EDI.com
EDI/ALE answers in plain English.
http://www.sap-edi.com/

The SapFaq
Email-based peer-to-peer technical support from experienced professionals. Home of the original MIT-sponsored SAP-R3-L Technical Support Forum. Free to qualified professionals. [Membership required]
http://www.SapFaq.com

SapPoint
Documents and screencams on topics of ABAP/4 programming
http://www.sappoint.com