It's possible, but against PP rules. They only want one account per person, and you risk getting your account(s) frozen/closed if you are found out (they will tolerate accounts on different 'skins' though)
You can make up bogus names, sign up your pet etc, but you are going to have a problem funding your account because they will notice if you use the same creditcard/neteller acct twice. I'm sure you can fool them if you really try, but I'm not sure it's worth the trouble. Besides, it's not very ethical (maybe even illegal).
The best way to get multiple accounts is probably to sign up non poker playing friends and family members (with their persmission ofcourse).