Just found this on the GTP forums

http://www.gtplanet.net/forum/showthread.php?t=185890

Basically, get your B-spec drivers into online mode. Then go into remote races and put your PS3 into server mode.

Download this widget and it will automatically choose one of your drivers and then randomly picks out b-spec drivers from your friends list and set up a full 16 car race. Runs the race, everyone gets cash and then it starts all over again automatically.

Great way to build up loads of credits for you and particularly your friends.

So get it started, put all your B-Spec drivers onto online mode and get it grinding for cash and b-spec xp!

Put your PSN name down if you want to be added to my friends list for some cash