Been there done that, However a couple of them have blown now. Not much of a bother as the whole lot is going to be replaced this weekend.
Like Paul says it's not hard, Remove the gauge cover (about 4 screws)
The hard part now is to pull off the gauge pod from the dash without snapping the brittle plastic clips. (done that on mine but holds ok with 1 of 3 left)
Next you need to remove the wireing looms and the speedo cable (small pliars would be usefull here)
The whole instrument pod will now pull away from the dash and you have clear access to the bulbs.
And now for the famous phrase, refitting is the reverse of removal.