Hi Mattb22,
I'm sure you'll love Oludeniz - it really is beautiful.
As far as Dalaman Airport is concerned, food and drink is very, very expensive there; but that's only something to bear in mind on your return journey. Trolleys cost £1 (in English money) - that's if you need one of course.
If you're not travelling with a tour company and you need to arrange your own transfer, an airport taxi will cost you approximately £30 - £35 to Oludeniz; I think that's also around the going rate for a private transfer. Timewise, a car from Dalaman to Oludeniz (going at a good speed) will take about 1 hour 10 minutes.
They do have a couple of diving schools in the area, and if you go into Fethiye Town to the harbour, you'll find a few different boats adverising various diving trips.
The best restaurants are in Fethiye Town - this is where you'll find the true Turkish restaurants. But Oludeniz (and Hisaronu) have some very nice ones too - although they are much more 'touristy'.
The Secret Garden, and the Olive Grove in Oludeniz are both very nice.
If you go up to Hisaronu the Oasis, Robin Hood, and the Olive Tree are all very good too.
Hope this helps.
Strawberry