Side mount also known as Side Control escapes all depend on where the person's hand is by your hips.
If they place your hand over your opposite hip, take your knee closest to the opponent and drive it through the crease of their hip. Use your knee to create space and grab half guard (you may get full guard if you are quick enough).
If the person's hand is where it should be, blocking your hip, walk your hips away from them until you are in line with your opponent and turn into the turtle position (on knees with hands on ground) and work from there.
From bottom of mount position, as Fedor said, use your elbow escape. Use your elbow or hand to push your opponents knee back and slide your leg under and then over their leg to gain half guard. Place the same hand as the leg you have grab for half guard across the neck of your opponent (as if you were going to do a Gi choke) and use that to create a little space while turning on your opposite hip. Pull your other leg out and grab guard.
Or if the person places a hand by your collar or chest, trap that hand and the same side ankle, hip up and roll (umpa) to that side.
Hope this is what you are looking for.
Last edited by mr08sports; 08-22-2009 at 10:49 PM.