*In order to have cydia, your iPhone/iPod must be jailbreak. If you haven’t jailbreak, go to blackra1n and download for Mac or Windows. Tutorial on how to jailbreak here .

Nr. 5 : Winterboard

It’s one of the top reasons someone jailbreak his iPhone or iPod. Through Winterboard you can customize your iPhone/iPod with unique themes, icons, slider, and other cool stuff. The bad things is that on 3.0 firmware it doesn’t support keyboard themes. Although it works fine on my 3.1.2 iPhone 3G 16Gb.

Nr. 4: Cycorder

With Cycorder you can record a video through your iPhone/iPod and upload it on your computer using SSH connection. It’s a great application.

Nr. 3:  Five icon dock, Five-Column Springboard, Fivelrows GUI

Those 3 applications modify your springboard to have 5 icons per page, 5 columns per page, and you can have 5 applications at your dock instead of four.

Nr. 2: Installous

Amazing application! You can download directly from Appulous cracked applications to your iPhone/iPod. And completely free!

Nr. 1: iBluetooh

It’s the only application that allows you to exchange data through bluetooth with other devices that have bluetooth too!

Also, check out Terminal