Motorola V400

I currently have t-mobile and want to buy another phone without extending my contract and have decided that I want to buy the v400. As i understand it, they come "unlocked" from Cingular because they are world phones and are meant to be used with overseas SIMs (as well as my own tmobile sim card) anyway, I want to know if the phone will work with my t-zones service that I currently subscribe to when i put in my tmobile sim. Will it matter whether the phone was originally cingular or not? will this affect internet capabilities at all? Am i correct about the unlocked aspect and could somebody please help with the TZones part of my problem? THANKS!