tranny fluid change - what's the best way to do it?

[thecheese429]

The time has come to change the fluid *clank grind* *Bang!*
if you get the point. it's become hard to shift and I think a fluid change would help it out more than a lot. I was wondering if I should just drain the fluid and filler back up, or would it be relatively easy to open it up and clean it out. would it be ok to flush it with something? could I use a blow gun to clean it out?

thanks