Tax and other fees

Does anyone have any advice on where I can find how much I need to charge for taxes and other fees?

Each state will have their own utility commission, which may consider voice-over-internet as a taxable service.
Also, you can check with each state's department of revenue.
As far as the FCC is concerned, VOIP is not a taxable utility, other than for originators (like VoIPo, VarPhonex, etc...).