You can use these calculators to calculate thriathlon split, swim pace, bike speed, running pace, and more..

TriCalc3 - An excellent Triathlon Calculator - Swim, Bike, Run.
This free online tool will calculate swim pace, bike speed and running pace. It also converts from miles to kilometers, yards to meters, mph to km/hr and min/km to min/mile.

Triathlon Split Calculator online
You can use this Calculator to work out on your splits, pace and speed across the swim bike run legs of a triathlon to achieve a given time.