One of the things to come out of the T-Mobile G1 launch event today was the structure of data pricing for the device. Sadly, the no-data-plan-required option didn’t pan out, and users of the G1 will be required to purchase one of two data plans. The $25 plan includes 400 text messages and ‘unlimited’ data for email and web access and such. The $35 add-on plan changes the text messages to ‘unlimited’ on top of the unlimited data.

In both cases, the phone can not be used for tethering with a laptop.

Considering that T-Mobile appears to be putting a 1GB soft cap on its 3G data access, that’s no surprise. Once users break the 1GB limit for the month, T-Mobile says that their data rates will slow down to 50Kbps – less than regular EDGE speeds, though still good enough for email. It’s unlimited data, but certainly not unlimited 3G data.

Remember, too, that the G1 also supports WiFi, so you can always use that.

Update: T-Mobile has since rescinded the 1GB data cap for the T-Mobile G1.