hi ppl

i'm needing some help... i have a 5510 and i have several sim cards... i want to know 3 things:

1. is it possible to have 2 sim cards in the same phone working at the same time? only when i receive phone calls. i mean, having 2 sim cards, if i get a phone call in any of them, i will be abble to answer?

2. if it is possible, i would like to know a relyable source to buy it, if possible in Portugal... and if it is not possible, also a relyable source to buy a traditional dual sim to nokia 5510 in Portugal.

3. i want to unlock my phone... i have the usb cable that comes with the phone... how can i do it?

thank u all