EDIT:You need BSD Subsystem installed before you install this!
here is a repository ipodtouchmaster made to get all the iphone applications for free including the webclips and wiggly icons. So you need a jailbroken 1.1.3 to install this. It does NOT give you any of the iphone preferences!!! so your ipod stays an ipod but with the iphone apps! now to use the mail.app you need to install 1.1.3 fix mail to save your password. that is included in my source.
Add this source to your ipod:
http://ipodtouchmaster.com/files/repo.xml
Then go to category The iPhone 1.1.3 Apps. install the package called The iPhone 1.1.3 Apps.. and there you go! then install 1.1.3 fix mail if you use the Mail.app.