I can't really offer much experience with a rack as it were, but the missus is rather gifted in this department and swears by both title nine sports bra's AND the patagonia zip front heavy duty c/d sports bra.
As far as running, the key I've found is to find a program that has worked for beginners and stick with it...they include something like this to get yourself some stamina:
Walk/Jog for 30 minutes. Walk for 5 minutes and then jog for 30 seconds. Follow that sequence for the entire workout. This is your first taste of running. Do not run for more than 30 seconds at a time. Run at a pace that is fairly comfortable.
And they all include rest days, and REQUIRE discipline.
The biggest problem for beginning runners is setting your goals/expectations to high and then either injuring yourself or losing interest.
I found this eight week guide with a quick google search:
http://www.runningplanet.com/article...article_id=340
Remember the key is SLOWLY building up to a run, without injury. Injuries and/or personal disappointment are quick paths to quitting.
Good Luck,
-bear