Its really hard to say exactly how much you will be making just because there are so many variables. You can start by just searching for military pay tables in google - you will be an O-3. To this, you have to add BAH/BAS, which is tax free pay for housing and depends on where you live but is usually around 2000-2500 per month unless you live in a real **** hole (which is entirely possible in the Army, not as much in the Navy). There is usually a 3% per year pay raise increase on basic pay, and rates increase for years of service. Plus you get special pay for family med, which is 20 g per year currently, board certification pay, and other special pays - it is impossible to say if these will increase or not in the next few years...
A good estimate would be:
[0-3 over 4 (after residency) - $4,722.90 - taxed
BAH/BAS - estimate $2000 (could be more, could be less)- not taxed
Monthly variable special pay - $416 (taxed)
Board certification pay - $208.33 (taxed)]
X 12
+ Annual incentive pay (Family Med) - $20,000
= 108,166.76