You will need a newer version of Photoshop like CS or CS2 (version 8 or 9).
The nice thing about Canon DSLR's is that they have a very good RAW conversion program that comes with the camera. Other with other DSLR brands you have to pay an extra $100-$200 dollars for their RAW software.
Exception is Pentax.
On the CD-ROMs you got with your 350D is a program called DPP. That is the RAW conversion software. On Canon's USA site you can download the latest version. (1.6x is on the CD i think, 2.06 or so is downloadable)
Canon EOS 350D, Tamron SP AF 90mm F/2.8 macro, Sigma 18-50mm F2.8 DC EX, Canon EF 70-200mm f/4 L USM, Tokina AT-X124 Pro 12-24mm F4, Soligor 1.7x C/D4 DG Teleconvertor, Manfrotto 724B tripod, Canon Powershot S30