Kuala Lumpur City Centre is compact enough to walk around but any attraction more than about 30 minutes away may leave you feeling drenched and exhausted.
BUS. There is a pretty good-value bus service using (mostly) clean,fairly new buses with aircon
Around the city,RapidKL http://www.rapidkl.com.my/ is the main operator.The service can be a bit overwhelming and best avoided at peak-hours but they go just about everywhere,and at RM1 per trip it may be worth getting lost every now and again.
TAXI. If you are very,very lucky you may find an honest taxi-driver who has a clean cab,uses the metre and knows where he's going.Otherwise you'll get overcharged by about 3 times the meter rate-or higher if you look very wealthy or very gullible..or both.
Taxis should,by law use the metre but few in the city do,mainly because the fares are so cheap that the driver wouldn't make any money if he used the meter (they say)
Fares will be increasing from 1st August- by about 40% let's see if the situation improves.
If you're selected cab refuses to use the metre,you can walk away and try another one,or you can try negotiate the fare.Anything more than RM10 around town should be questioned
MONORAIL. http://www.monorail.com.my/ Although it's a confusing walk from KL Sentral, the monorail is an interesting way to traverse the town but apart from Bukit Bintang station for Shopping,Medan Tunku station for Kampung Baru and Bukit Nanas station for Hard Rock Cafe and the bars on Jalan P.Ramlee it doesn't really serve the visitor that well.But you do get an interesting "roof-top" view.
LRT. There are 2 LRT lines serving the city centre and suburbs.It's fast and efficient (most of the time) and inexpensive.The 2 lines are not very well integrated except at Masjid Jamek station
KL Hop-on Hop-off. http://www.myhoponhopoff.com/ Is a bus service specifically aimed at visitors.The buses run in a continuous loop around the city covering 40 attractions,served by 22 stops.There is an audio commentary and you can get-on and off as many times as you want.First bus is at 8.30am and the last at 8.30pm. and run at 20-30minute intervals.It's a good way to get an overview/orientation of the city.A day ticket costs RM 38,whilst a 48hr ticket is RM65