What app will STORE my other apps for switching ROMS?

New to being rooted and doing various ROMs right now to see which one I like. I lose my apps every time I switch from one ROM to another and would like to know if there is an app that will save and restore all installed apps?
If so, please tell me what it is. I've done a bit of searching on here, but haven't found anything solid.
Thanks in advance.

 

Downloading Titanium right now. That's the info I needed.

Also, what are the major advantages to switching to FROYO? (this is the wrong section for this, but I figured I'd ask in here instead of starting a new thread)

 

+1 to Titanium Backup. Also, get the Donate version or else when you go to reinstall all of the apps you'll have to manually say ok to each one. With the donate version the batch will install all the apps w/o having to approve each one while it's trying.

 

You should just use Titanium Backup. It's cheaper and it's easier to use and has more features. I used the free version of Titanium backup and it worked so well I had to donate. And, like the guy up above said if you donate you won't have to manually click OK for every app that you want to reinstall. Titanium will do everything for you.