PE Interview TImeframe for First Year Bankers

So I've heard that first year analysts looking to get prominent PE jobs start interviewing around Jan of their first year (so for newly minted analysts that'd be Jan of 09)

First ? is this - obviously a lot of the PE shops hire on a set schedule much like banks do - is January really an appropriate time to start scheduling interviews?

Second? - what's the best way to start preparing for interviews/setting up interviews?

Third? - what the hell do they base hiring decisions off of in January as I've only been on the line for three/four months at that point? How imp is undergrad GPA if you're at a top bank - GS/MS/JP in a solid product group?

Fourth? - is it even worth interviewing out this year? Mightn't it be better to hold off an try for a third year analysts position and interview such that I'd leave after that? I imagine that mkt conditions will have improved/job opportunities would be more at that point?