There are two ways to fly a crosswind approach and landing, crabbing, or sideslipping, both work, I personally think the sideslipping method is easier, but in some aircraft it can be undesirable for a number of reasons.

There is an easy way and a hard way to fly a sideslipping approach in a crosswind.

Bear with me on this explanation, it is how I explained it to my students.

1. Primary effect of ailerons is roll, secondary effect is yaw
2. Primary effect of rudder is yaw, secondary effect is roll.

If you change one, you will have to compensate with the other.

If you are constantly trying to change both, you will be forever chasing your tail.

In this example lets look at a cross wind blowing from the right. IE pushing you left.

On final approach in a crosswind.. do THIS.

Line up with the runway. Nose pointing at the runway.

Now roll slightly right, IE bank towards the side the cross wind is coming from. (this puts your lift vector to the right so the horizontal component of lift will correctly compensate for the drift)

The aircraft will want to turn right and change heading. Stop this by applying Left rudder ( away from the crosswind )

Now here is the critical part - (it can be easy or it can be hard.. I like easy) LOCK your foot in position. IE Hold the rudder and don't move it.

You now only have to use aileron to make slight adjustments to your direction to fly to the runway. You are only adjusting one control, this is easy, instead of constantly adjusting two controls (hard)

Your aircraft is now in a sideslip.

In a no wind situation this configuration would make you drift right, however since the cross wind is making you drift left, they cancel each other out.

In a light aircraft you can hold this rudder all the way down to the runway and even during the flare. Your nose will be straight and you should land right wheel first.

Perfect cross wind technique and easy as pie.

This technique works perfectly for RC planes also.

Assume you are landing left to right, wind is blowing from behind you, IE a right cross wind, making your plane drift left as seen from the plane.

Roll right slightly, apply slight left rudder and lock your rudder position, don't keep changing it. Now fly to the runway adjusting your direction with ailerons as you would in any other landing and land with this rudder held. It works great in crosswinds.

Reverse everything for left crosswinds..

This sideslipping technique works in any aircraft but is not used in larger corporate jets or airliners. Aside from being uncomfortable to passengers, the main reason for this is that any bank on touchdown with a long swept wing may result in a wing tip strike (just 6 degrees of bank will do it in some corporate jets) so the technique used in larger aircraft is crabbing with wings level and using rudder to straighten the nose just before touch down.

However, the side slipping method works really well in light aircraft and I have had students use it to land quite easily in 30 Kt crosswinds in a little Robin 2160 (landing speed 65 Kts)

Here is a really good video, most of the planes use the crabbing technique but at 2:46 the SAAB is using the sideslipping method, you can see his right wheel touch first, the bank angle is held during the approach and the nose is generally in line with the runway.

http://www.youtube.com/watch?v=9PdUdaXDHm4 Another good one that demonstrates both methods with RC aircraft.

http://www.youtube.com/watch?v=3SmTxX4TLww