I just got my 3rd Android phone, the problem is that I must reinstall all my applications every time I get a new phone. Is there any way to store the apps on the SD card so that I can insert the new card and all my apps are there?
I would prefer solutions that don't require rooting the phone.
This is a feature that requires Froyo, so unless you have a Nexus One you'll need to either root your phone (which you've already said you don't want to do) and install a Froyo ROM or wait for your manufacturer/carrier to issue you Froyo in an update.
Either way, moving apps to your SD card is pretty straightforward. Go into Settings, then Manage Applications. There you should have the option to move your apps to your SD card.
I'm stuck with 2.1 (HTC Desire) for the time-being, so the APP2SD provided by Froyo isn't available to me.
I use Appbrain which allows you to keep a synchroised list of the apps installed on your phone in your own (free) online account - and then the Appbrain app on the phone will then automatically allow you to reinstall the apps you had before. I've used it numerous times when re-flashing my ROM.
Downside - it's a fresh install; so you lose any data within the apps. Upside - free, easy and takes the ball-ache out of reinstalling; it also allows you to install apps on the phone directly from the appbrain site.
Hopefully the next time you get a phone it's Froyo or better. I installed Froyo on my Nexus One and it knew what apps I had installed on the previous system and started to downloand and install a fresh copy for the new OS. Only downside was that any data with those apps was lost (like the data from My Tracks) but the NEXT time I upgrade I would imagine even that data will be transfered to the next phone!
Google has now launched (a while back, I believe) a website for the Android Market you'll find on your phone at market.android.com - just log in with your Google account that you have your phone registered to. From there, you can install apps, browse ones that are compatible with your device, and also view all of your purchase history and library of apps, books, and movies found on your device. I'm not sure if it will let you transfer apps back and forth between phones, as I only have one device, but I'm pretty sure that there is likely a way to re-download purchased apps from there after you de-activate your first phone. Hope this helps!