I followed this guide: http://startbitcoin.com/

I have started mining in a "pool" with this GUIMiner. According to my account on the pools site, after this "round" my estimated reward would be 0.00000169 BTC.

Could someone please elaborate on what is happening?
I have a wallet set up and everything.

What is a "round"? When does it "end"? Will my wallet be rewarded after?
Thank you!