Project Jedi is one of the successful TEAM that has carried out API Implementations for Delphi.
Visit them for API implementation helps in Delphi and Builder.

Delphi Links: 

Borland                        http://www.borland.com
Delphi32                      http://www.delphi32.com/
Delphi Deli                 http://www.delphideli.com
Delphi Exchange         http://www.delphiexchange.com/
Dr. Bob's                     http://www.drbob42.com/

Primary Site:

Poland                       http://sunsite.icm.edu.pl/delphi/
Australia                    http://ftp.powerup.com.au/webmirror/delphi/
Finland                      http://www.tietovayla.fi/borland/delphi/extra/super_pa/
Germany                    http://sunsite.informatik.rwth-aachen.de/delphi/
Indonesia                   http://bbs.stts.ac.id/public/delphi/default.htm
Italy                         http://www.programmers.net/mirrors/DSP/
United States             http://www.cdrom.com/pub/delphi_www/

Torry's Delphi Pages
http://www.torry.ru/index.htm
http://www.torry.webnorth.com/index.htm
 

Tomes of Delphi API Support Pages
http://www.cyberramp.net/~jayres

Wordware
http://www.wordware.com