Hello,
GSM is the technology used for Speak Out Wireless, and it is the most used technology in wireless handsets in the world today. 2G stands for 2nd Generation wireless technology. 3G (3rd Generation) is the newer technology than 2G. There is a good read about 2G here:
http://en.wikipedia.org/wiki/2G
and 3G here:
http://en.wikipedia.org/wiki/3G
Speak Out uses 2G.
As for phones, that is a personal preference. I picked up the Nokia 1208 with the "Buy a $100 top-up voucher, get a phone for free" promotion. That promotion is good until the end of this year.
I really like the Nokia 1208, and recommend it. It is a basic phone, but performs well. Phones and sim cards are up for sale on this site many times as well.
You may read all about Speak Out at their official site, found here:
http://speakout7eleven.ca/
Welcome to speakoutwireless.ca!