You can watch your personel stats for TF2.
Open your steam and go too community in the right upper corner you can see your stats there.:)
If you have TF2 offcourse.:)
What can you do with the achievements then?
You can view the stats in game too, and it shows them as maps load.
But other than encouraging you to play that little bit harder they don't really do anything.
There are acheivements like that in Ep 2 and Portal as well. They correspond to the XBox Live Achievements that up your 'gamerscore'. Given that they had to make them for the XBox version (I believe all 360 games have to have them, and all have to have a certain number of them?) they probably figured they might as well pull them across to the PC version to encourage people to play until they had got them all.
can this be linked to your Xbox 360 account as really dont want 2 versions of the same game for the two platforms
Not as far as I am aware. The only reason they are in the PC version at all is having done the work to create them for the 360 they might as well include them on the PC just to try and encourage people to play the games for longer.