The easiest way to get to Kajang is by commuter train. From the main KL Central station (KL Sentral), go to the KTM counter and buy a ticket to Kajang. As of right now (Feb 2004) I think it costs 2.80 ringgit one-way.
The ride should take you right around 30 minutes. Once you get out of the train station, there will be plenty of taxi drivers willing to take you anywhere. It will probably be 5 ringgit to take you to town. Or, you can wait for a bus out front (60 sen for the red and white, 70 sen for the blue and yellow). Stay on the station side of the road; that is, you want to head to the left.
OR, you can just turn left onto the road in front of the station and walk into Kajang town. It is about a 15-20 minute casual walk.
Once you're there, read my satay review here to see where to go!
If you're doing public transportation, it's actually quite easy in Kajang. You have three choices: taxi, sum bus or bus mini.
Taking a taxi from Kajang to anywhere , like the train station, will usually be at least 5 ringgit. Even though the train station is only about a 15-minute walk. But it's hot, so it's sometimes worth it.
The "sum bus" and the "bas mini" follow pretty much the same route. The sum bus is big, red and white. Cost varies, but starts at 60 sen. If you go to the university (UKM), it's 1.30 ringgit. The bas mini is a short, blue and yellow bus. Costs 70 sen to anywhere. Flat rate.