This machine will support OSX 10.8 (Mountain Lion) which is the latest version but it will require more RAM to be comfortable with it.
this machine max's out at 4GB. Buy it from Crucial.com
Alternatively, you could run a lower version of OS X, perhaps 10.6 (Snow Leopard) which was a little less demanding. Still go with the max RAM though.
How you get to 10.8 or 10.6 depends on where you are now. Until we know that, we cannot be certain of the route you will take. Snow Leopard and Mountain Lion were both upgrades from Leopard/Lion and sold for $30 (ish).
In the case of SL, it was possible on most machines to go from 10.4 straight to 10.6 and then to 10.8.
Some people even went directly to 10.8 but that was a great leap of faith that did not always work.
As for FaceTime, 10.6.6 was the first software to support it.
HI,im going to buy a used macbook pro 17" for my daughter its an early model core 2 duo 2.4ghz 2gb ram only been used a handful of times im not sure what osx is on it i would imagine it has never been updated since bought in 2009, will my daughter be able to facetime on it.If not how much does a new operating system cost also with this macbook will i be able to install the lastest osx or is this machine not capable of running it any answers would be very much apppreciated regards steve