Hi ,
what is the easiest way of geting from Changi to JB. We arrive at about 15.00. Thanks.

The easiest way to JB from Changi airport is to take the MRT train from Terminal 2 MRT Station to Tanah Merah MRT Station (two stations away), alight on the left side and board a west-bound train to Jurong East MRT Station (20 stations away)
Alight and change to a northbound train at the centre track to Kranji MRT Station (5 stations away). Get out from the station and change to an SBS Transit Service No 160 or 170 from across the road or a Causeway Link Bus (yellow colour) which will take you to the Woodlands Immigration Complex, and onwards to Johor Bahru.
Travelling time between MRT Stations is about 2.7 minutes, and waiting time for trains normally do not exceed 5 minutes on average (it may take longer for off-peak hours).
Another option is to take a bus, SMRT Service 858 from the basement of Changi Airport T1 or T2, which will take you from one terminal to the other at Woodlands Regional Interchange (Bus and MRT Station). At Woodlands RI Bus Terminal, you will transfer to another SMRT Service No 960 (I'm not too sure of the svc no. but you can confirm it at the bus terminal) which will take you to Woodlands Immigration Complex and onwards to JB (This can be a faster option if you do not encounter any traffic jams on the roads).
The third option is to take the MRT train from Changi Airport T2, alight at Tanah Merah, change to a westbound train and alight at the Bugis MRT Station (8 stations away), get out of the station, turn left, get up the escalator, turn left, take the diagonal path on the left hand side and walk to the Queen Street Bus Terminal and catch a Singapore-Johore Express bus. You can also take SBS Transit Service No 170 (which also starts from the terminal) but this is not advisable as it is a normal service with many stops along the way to Woodlands. If you are in a group, and do not mind paying a bit more, you can also take a taxi from the terminal there (only taxis at this terminal are authorised to carry passengers from Singapore to Johor Bahru.
The last option is to catch a taxi from Changi Airport and goes to either Kranji or Bugis to change to Bus, or take a taxi direct to Woodlands Immigration Checkpoint and walk across the Causeway to Johor Bahru.
Have a nice journey.

Wow, totally great answer Sam - hope you got a topic stored because this question comes up so much.
Sampan, this should be kept in a sticky. I frequently see this question being asked in the forum.
Gof, do u have a time constraint? If you are in a group of 4, perhaps you should just take a cab. This will be the fastest option.

i hope this is not too late.
the best way for me would be to take the taxi from the airport to Johor Bahru taxi terminal (it's called ro-cher road - just say to the taxi driver Johor bahru taxi terminal). Around $10-19. then from the terminal you could either share a taxi with 4 other passenger in a taxi ($8 per person) or just have the taxi by yourself (i would say around $45 per taxi) they could send you straight to your destination in JB city centre area (slow talk with the driver).
i personally wouldn't used the MRT since it takes ages (personal experience). the bus again would be a hassle since you have to get off walk to the customs and wait for a bus (2 times in singapore and malaysia). if by taxi you just have to sit in the taxi and i can guarantee it is much faster too.
Just to clarify, Queen Street, Ban San Street, Rochor Road and Ophir Road are close to one another in the Rochor area.
The Bus / Taxi Terminal is at the junction of Queen Street and Ban San Street.
The taxi charge to JB is SGD32.00 or $8.00 pax if 4 passengers (maximum number that a taxi can carries).
The taxi charge to Senai Airport (for those who want to go there to catch an AirAsia flight) is SGD55.00.
To call the taxi terminal "Johor Bahru Taxi Terminal" is a misnomer and can create confusion for a taxi driver who may not understand your intention.

hehehe...ditto...the fastest way is by cab, read the question. It does not say the best way, it ask the fastest way :P