~via BB (wap.rabroad.com)~ok so I called t mobile about the information you will need. First you need one the following phones, samsung t-209,t-319,t-509,t-619, 8100 (perl) or nolkia 6103 or some other new nokia that comes out next week, also you need the v3 razor...
On all single line plans you can add it for anywhere for 4.99 to 9.99 on a family plan you can select to remove the mobile to mobile and get 5 numbers each line, or keep the 5 number and add m2m for 6.99. I will you keep you updated on any new information I get