I realy want the Nokia N96 but Its on contract. . Can I change. . [[ please help

[OmgYouDumbShite]

mee !! ]]? I realy want the Nokia N96 but Its on contract and I dont have the money too pay every month.
Can I just pay the £25 for one month. . then change the simcardd to say T-Mobile ??

Pleasee helpp I realy need this phone !