Jason Kit got a update to version 1.2. Jason kit is a app that will let you make backups of your installer sources and backups of your maps. The new features for version 1.2 are the possibility to search for contacts and editing the number before you call or sms someone.
» Jason Kit 1.2 - Swap your iPhone installer sources + maps

Jason Kit is actually a old app named iLM renamed.
The app let’s you swap between several maps and your installer sources.
I already discussed a application that let’s you backup your maps and switch between them. It was called maps offline and you can read the original post here.

What’s the big difference about maps offline and Jason Kit?
» Swap maps cache and installer sources with Jason Kit1.0b1