Well, the OP hasn't even signed onto this site since March 20, but I would like to better answer the questions asked here as he/she asked again about using a Straight Talk SIM on that date.
Where the OP asked about 'unlocking' the phone it was intended to ask if the phone could be SIM unlocked. The simple answer is no, since the A855/Droid 1 phone is not a global phone and has no SIM slot.
As far as rooting it, should the OP still wish to do so, there was good info posted, and I have more in my guides in my sig, however that would have no effecton whether or not the phone could use a Straight Talk SIM card, however, it _might_ still be able to be used on Tracefone but it is easier to get it working on PagePlus.
@sherri: Same here!
good luck