Sorry if you already knew this but I found a way to get OTA games and themes to my phone without a data plan. I got my pearl for free and can't afford bbinternet yet and I'm sure others would like to do this as well.
1) Download the simulator for your model phone as described in this thread:
Take the 8100 for a test! 8100 FULL Device Simulator released. - RIM Blackberry Forums - Pinstack.com
You need to have the simulator, the email and mds simulator, and Sun JDK 5.0 for it to work properly with the internet.
2) Run the mds simulator from Start>All Programs>Research in Motion (It will open up in Dos, just leave it alone or minimize it)
3) Run the device simulator (same location as step 2).
4) Use the browser in the simulated phone to download games and themes or whatever.
5) Follow the directions on Kradest.com thanks to Kradest on how to backup OTA and 3rd party applications, however, when you get to step 5 of his instructions just stop and come back to this thread and read where it says "Edit:" in this post below.
Kradest.com
NOTE: DON'T WIPE YOUR BLACKBERRY if you are only trying to get games and stuff to your phone.
I had a little trouble following his instructions though as I could not find the files saved to my pc. I ended up just disabling the simulated usb connection and connecting my actual phone to let it go through the wizard and switch the games and themes over to my phone. But they show up in app loader to uninstall and reinstall so it works great.
EDIT: I found out it doesn't allow you to reinstall like stated above. It will disappear from app loader if it is not on your phone. I added a post below describing how I was able to find the files that save to your computer. Or check out this link to where KRAD cleared things up a bit about that situation:
KRADEST, I got a question for ya. - RIM Blackberry Forums - Pinstack.com
I found some awesome free OTA only downloads at mobile.blackberry.com and
Free Mobile Games Community for your Cell Phone