If by Internet you mean Internet, it's already there.
If by Internet you mean "CDMA data" be it EVDO or 1xRTT, then no. The CDMA protocols only support EITHER a voice call OR data transmission, and not at the same time.
You can use WiFi data and have a phone call at the same time.
You can't use CDMA data and have a phone call at the same time.
There's nothing to "hack that method." All that maps does is cache the data. If you talk long enough or start talking before trying to get driving directions when outside of WiFi range you'll find maps doesn't work either.