The first obvious question is-did it come with its own wall bracket?
If so then Tolemans answer covers most things.
If not then your first priority is to get one.
In the last year I have fitted 2 x 37" flat screen TVs to a wall. This is no great problem but assuming you have, say, at least 2 other boxes(eg SKY or DVDR)to sit below it you will need to consider how much space they will take up.
Altough I bought a cable management system(also fitted to the wall) in retrospect i think it might have been better to buy a clear glass table that already incorporates a bracket onto which to fit the TV.
I should add that I don't have a fire or surround to contend with.