YES! PRONTO WORKS FOR LINUX!
--------------------------
1: Download WINE off the software portal
2: Using Wine-Doors, download Internet Explorer*
3: Use Internet Explorer and go to the download page for Wimba Pronto
4: Download Pronto and run the installer
5: Open Pronto and talk to your classmates!
--------------------------
* With linux, the download page wont let you download pronto because it can tell you're using an operating system they haven't gotten pronto to work for. With wine, it simulates Win XP and allows you to download Pronto.

I hope this helps anyone who needs it!