Touch Mail is a webmail system tuned for the Iphone/Ipod Touch. With Touch Mail you can use any email service like Yahoo! Mail, Gmail, AOL that provides the POP protocol access.
Written in PHP5 and it does not require any database support.
This is an open source application which can be downloaded from sourceforge but looks like a fantastic idea if like myself you have email accounts with many online providers.
IPhone gamez is a collection of small utilities and games for the IPhone. At the moment there is a chess game.
Again this is an open source project so you can contribute if you wish and you can view the source code so you could learn about creating your own games and utilities.
More details can be found at IPhone gamez sourceforge listing page
IPhoney is an open source browser simulator for the IPhone for MAc OSX users. This software allows developers to test various web site that they create in accurate recreation of an IPhone even if they do not actually own one, this of course is extremely useful if you were producing a website targeting these users.
For the programmers out there this app is written in objective-c and is open source. The official source forge page is listed below.