Our readers have noted, and now several sites are reporting that it appears that Apple is gearing to launch an official iPhone Web Application directory.
AppleInsider believes such a directory may launch as early as today. Our readers, as well as 9to5mac, have submitted observations that Apple's recent download's RSS feed contains iPhone web applications and a link to a currently inactive portion of Apple's website: http://www.apple.com/webapps/
As the iPod Touch uses the same mobile Safari web browser as the iPhone, such a directory listing would be applicable to it as well.
Currently, Apple's supported and official method of developing 3rd party applications is via the Safari web browser. Unofficial native solutions have been derived as well and are still in the process of being updated for Apple's latest firmware release. Such solutions are not supported by Apple, but have proven to provide more features.