Our BlackBerries do so many cool things. MLS access is definitely one of them. It's small so you'll still need to do the big jobs on a pc but it works in a pinch!
Click on the browsert icon (the world) from your home screen.
To the left of your "mouse" is the menu key (has 7 little dots on it), push that.
Highlight "Go To..." and click.
The "www" is already there so type in prewireless.com
It will ask for license ID and password, enter:
License ID: 196946
Next enter your MLS # and password as you would enter it on NTREIS to log into MLS on your pc.
Most importantly save as a bookmark.