T-Mobile comes out officially to clarify things regarding the G2
They said, “Wi-Fi Calling and tethering/Wi-Fi sharing are not currently supported on the T-Mobile G2. T-Mobile knows these features are important to consumers and we're working to deliver them to G2 users in the future. We have nothing further to announce at this time.”
Although it means that we won't be seeing it in the near term, it appears as though they'll be getting it out to users nonetheless – but now the only question that remains is exactly when it'll be available. Still, T-Mobile G2 owners still have a lot of be happy about since the Android powered smartphone packs HSPA+ connectivity.
And even though the G2 is running Android 2.2 Froyo, which has native support for mobile hotspot, T-Mobile is yet content on opening up the flood gates for it.
T-Mobile G2 Specifications