Honestly to save a headache I wouldn't bother flashing. It would be much easier to sell your droid and buy a gsm android and just pop in the sim and you would be good to go.
Even if you do flash it successfully I don't think straight talk is as acceptable as say boost. Plus it is a huge pita... I tried flashing a sprint phone to page plus and it never really worked out very well. It would be much easier to go gsm. Then you can switch prepaid carriers all you want.