Not sure if you have seen some of these....
http://www.baseballanalysts.com/
A pretty good source for info on prospects and articles. They even talk MLB baseball at times.
http://www.minorleagueball.com/
Another Baseball blog by John Sickels, you might know him as he has worked with other places. Both this site and the one I mentioned above have useful links to other things besides prospects if you want to check those out.
http://www.attheplate.com/rookies.htm
It does mainly give stats, but if you scroll through the day, at the end it will have quotes and links to any articles/info on prospects that day. If anything it's easier to look there at times instead of going to every site yourself.
http://www.ondeckbaseball.com/
If you don't like just reading stats, then this guy goes through the day in the minors w/ a bit of description to go with it. Sometimes though he lags a bit, but he also has his league/organization rankings.
Anyways those are the ones that I come to my head quickly that are free.