How to run Cydia in the background using native multitasking on iOS 4.x
One of the major drawbacks of Cydia is it's inability to run in the background. I like to be able to multitask when I am doing anything on my phone, including installing 3rd party applications. This tweak will allow you to background the Cydia process. Of course, this tweak doesn't come without it's setbacks. @saurik has stated many times that he has disabled backgrounding for specific reasons. Namely, it will eat up a lot of memory and it is possible that you could experience errors installing apps/tweaks/themes while running certain other processes.
Step 1: First navigate to the Cydia.app folder using either SSH or directly from your device via iFile. You can find the folder here /var/stash/Applications/Cydia.app. Once you are in the Cydia.app folder open Info.plist with a text editor.
Step 2: Once inside the Info.plist file, locate the line towards the bottom that contains:
<key> UIApplicationExitsOnSuspend </ key>
Step 3: All you have to do is change the word "true" to "false and then save the file. After that simply reboot your device and Cydia will now be able to run in the background when you hit the home button with it open!