QUOTE(rebeccajo @ Apr 23 2007, 07:05 AM)

First - IS AP void once the greencard is approved? Actually void? It has no use whatsoever?
If one needs to travel before the greencard is in hand, but computer systems can prove you are a Perm Res, but just don't possess the physical proof, is it ok to travel?
Yes, AP is voided
when your Permanent Resident status is granted. This often has nothing to do with getting the card.
If you need to travel before you have the Green Card, you need evidence of status, aka an I-551 stamp in your passport.
IF (big IF) you get approved at your interview, AND you have imminent travel plans, bring proof of your upcoming travel and prepare to beg plead and grovel. And cross your fingers. Your local USCIS officer should give the stamp.
Alternately, change your travel plans. You should not leave the US without evidence of status when you are a PR.
Yes, you can beg plead and grovel at the POE on return, and deal with the fallout then. I think (paraphrasing here) the rule is that anyone who makes a claim of PR at entry has to be admitted, and scheduled straight away to see a judge to sort it out. I don't know if that admission is a true admission, or if they are paroled in on some sort of administrative category (ie it wouldn't be the usual parole that we discuss here).