1. Party host invites friends

2. Once you receive invite, log off PSN via the XMB (hit your PS button, scroll to account management, hit triangle, log off)

3. Log back on, accept invite

It's a pain in the ass but the only way surefire way to get a party going.

You DONT have to turn off your PS3 or exit the game completely.

Also, if you're having trouble seeing people on your friends list even if they are telling you they are on just log off and log back on PSN.

This shit makes me miss Xbox Live so much.

Also, hit me up for games or add me, psn id is maximum_chill