It is easiest to find from under the vehicle.

Raise the front and support it safely. From underneath, look up between the
transmission and the bulkhead. The VSS is located on top of the
transmission.

Here is some information posted last year about changing it:

Using a pair of pliers, bend the flat clip on the securing pin out of the
way. (It does not go in to the hole; it just presses on the casting.) It
will probably detach itself when you do this. Grip the pin with a pair of
side-cutters close to the transmission housing and then use the
side-cutters to lever the pin out. You will have to keep repositioning the
side-cutters along the length of the pin as it gradually comes out.

Others have suggested clamping mole grips on the pin, then tapping the mole
grips with a hammer. I tried that, but it didn't work for me. YMMV.

Once the pin is removed the VSS is still a bit hard to get out. It has two
O-rings on it that make it a tight fit in the housing. DO NOT be tempted to
try to knock it upwards with a drift and hammer. This might result in the
sensor breaking, leaving half of it in the hole!

In the limited space available wrap a piece of rag around the sensor and
rock it GENTLY from side to side and twist it as you pull upwards. Take
your time and it will eventually come out.

I agonised for ages before tackling mine, but once I took the plunge I did
it in less than 20 minutes.

Note that you *will* destroy the pin holding the VSS in when you remove it,
so be sure to buy a new one when you buy the sensor!

HTH.

Post back if you need further information.

Chris.