I had a MoveOn.org password and got "pre-selected for the pre-sale" for the 10/1 Bruce/REM/Bright Eyes show in Philly... I logged on at 10 am this morning through their website, OK'd the disclosure conditions, requested my two tix ($78.50 + $6 in service charges each), got two "page busy" warnings, and on my third try (somewhere around 10:01:30 if you're keeping score) was told that there were no more tickets left.
I kept trying until about 10:15, maybe 20 times in all, but no luck.
I probably won't try for the Pearl Jam/Death Cab for Cutie show in Reading, which has its pre-sale tomorrow (8/20) at 10... if anyone wants my MoveOn pass, let me know. Can't say you'll have better luck, but it might be worth a try.