Assuming Google Voice is configured on SP1...
Physical Interfaces -> PHONE Port -> PrimaryLine : PSTN Line
Physical Interfaces -> LINE Port -> DigitMap:
([2-9]11|[2-9]xxxxxxS4|<**11>[2-9]xxxxxxxxx|<**1>1xxxxxxxxxx)
Does the third rule in the above DigitMap, ie: <**11>[2-9]xxxxxxxxx, assume that dialed 10 digit numbers are long distance? In my market there are at least 3 different area codes that usually are not long distance and 10 digit dialing is required for all local calls. To further complicate the process there are at least two area codes in an adjacent market that are normally long distance and would require a leading "1" but if the number is a metro number it can be dialed as a local 10 digit number. In this case I think I'd omit the third rule and the fourth rule would handle long distance numbers dialed with a leading "1". On the other hand, I could be missing something.