To be honest, it's all in the diet. Keep your routine simple. Don't "reward" yourself with food after workouts which is the downfall of one of my friends (he works out then pigs the fuck out and complains afterwards).

Heck at Wal Mart you can get a decent stationary bike for like 200 bucks and they put it together for you. I have never went over 140 lbs (135 is a good weight for my frame, 5'9"), but doing just 10-20 mins depending on how busy I am before work or before I go to bed helps me maintain.

As was mentioned earlier, get some weights, great way to burn calories.

Here's my well chiseled mug (j/k)

but really, I can probably pull off one those noob emo kid vids, someone hook it up!