In reply to Styx:
Pull-up's etc won't do much to keep the weight off because those kind of exercises build muscle.
When I snapped my ACL i did:
1.) Lots of cycling in and outdoors (are you sure you can't manage this yet? My physio recommended it). You can adjust the height of the bike seat to compensate for reduced range of movement.
2.) Rowing maching (leave your bad leg out of the styrrup)
4.) Laps of the pool - not breast stroke (bad for damaged ligaments, apparently)
4.) Watch your diet, especially booze.
5.) Lots of wanking. I've kept this up, even though my leg is much better now.