Well unlike Stephen and Don, I jumped in at the deep end and started using Raw when I bought the Minolta D7 Autumn 2001. Although previous to that I had processed all my own B&W and colour for the past 40 years.
I'm not suggesting that you should also jump in at the deep end especially as you are new to photography
So to answer your question CS2 is actually the latest version of Photoshop and has it's own raw convertor.
However all is not lost as you can download Pixmantecs "Rawshooter" which comes in two varieties "Essentials" which is freeware and is very good, or the "Premium" version.
http://www.pixmantec.com/. Both versions will automatically open converted images directly into photoshop if you so require.
No doubt there will be a steep learning curve ahead of you just learning how to use the D50, but just in case you're a glutton for punishment, have a read here
http://www.cambridgeincolour.com/tut...ile-format.htm
Harry