Other estimates have ranged it up as high as 25,000 people.
Check out the post here that has some pics too.
http://www.freerepublic.com/focus/f-news/2088086/posts
You can blast the local TV stations for the disgraceful, almost total blackout of this rally:
WPVI 6 ABC
http://abclocal.go.com/wpvi/feature?section=resources/inside_station/station_info&id=5770722
KYW 3 CBS
http://cbs3.com/contact
WCAU 10 NBC
http://www.nbc10.com/News/1433300/detail.html