What's the best way to get from stable to testing?

[wix@eskimo.com]

Greetings;

It seems that the testing dist has more good stuff in it than stable,
but how do I upgrade?

I tried doing a network install but neither of the choices to build
init.rd worked, so that was a few hours wasted.

I have a working install of stable/sarge running. Can I start from
there somehow, or is that even more involved and lengthy?

Oh yeah. When I get to that point, which kernel do I choose? I
have a P4 but I have no idea which to use except for 386.

Many thanks, again!
Dennis