hi, i need to change some of the fluids in my 02 wrx, it is 41k miles and I need to know how to make a transmission oil change, clutch oil change and brake fluid flush. I would apreciate if someone can give me detailed instructions or at least point me to a thread that does. Also i would like to know what fluids to put in each of the components. Any comment will be apreciated, thanks.

... clutch oil change and brake fluid flush....
You use the same fluid for both. At a minimum, a generic DOT 3 or DOT 4 fluid can be used, but for only a little bit more money, get Valvoline Synpower DOT 3/4 brake fluid for both. It is readily available in auto parts stores, absorbs water less easily than standard fluid, and has a much higher boiling point than standard fluid, both with and without moisture in it. Since your brakes get very hot, and if the brake fluid boils you lose brake function, for safety reasons the higher the boiling point the better.
As for how to flush/replace the clutch and brake fluids, since avoiding bubbles in the brake system is important for safety, and you need an assistant anyway to press on the brake/clutch pedals while you are dealing with the bleeder screws, I'd try to find somebody locally that can show you how to properly bleed the clutch/brakes (they don't necessarily need Impreza experience, just experience bleeding brakes/clutches).

Search on www.scoobymods.com

so clutch fluid and brake fluid are the same?, what about tranny fluid and diferential? how do i change tranny oil?

If you read the post above your question, you will find your answer.