First, get your loan information from NSLDS.
http://www.nslds.ed.gov/nslds_SA/
Then use this online calculator to estimate what your payment would be on a new Direct Consolidation Loan.
https://loanconsolidation.ed.gov/loancalc/servlet/Controller?controller_task=startCalculator
Also, research which repayment plan you would want to select for the consolidation loan.
http://studentaid.ed.gov/repay-loans/consolidation
It should be pretty painless but your loan servicer will likely change.