Here is a list of apps that can be downloaded free of cost & used. Thereby your iPod Touch's functionality gets enhanced many fold.
1) Skype for iPod Touch: Skype can be used for the iPod Touch as well. This turns your iPod Touch into a phone. You can operate the iPod Touch even when you are using the call functionality. Thus, the Skype application can enhance your iPod.
2) InstaPaper app for iPod Touch: This app lets you save an article you read on the web & enables offline viewing. This works without the internet connection as well. Through the InstaPaper you can view your docs& favourite web stuff even when you are offline. These pages can also be saved for later viewing. Thus, the InstaPaper is a revolutionary iPod Touch App.
3) EverNote app for iPod Touch: The Evernote App enables you to make a note of everything that you come across. Multimedia remembering is also provided by Evernote. Teh Evernote data can be accessed through PCs as well. Dynamic updation is also carried out by Evernote.
4) VLC Player for iPod Touch: This app is the most used app on PCs and mobile phones. But, this can also be used in an iPod Touch as well.This provides an interface between the itunes as well. Videos can be played effectivelu with the VLC Player.
Using these apps, the functionality, efficiency of the iPod Touch increases many fold.