Park Tool just released an improved version of their spoke tension conversion calculator. It creates a spider graph that allows you to see spoke tension like this;
It also flags spokes that are too tight or too loose which makes it easier to balance the tension. By having balanced spoke tension a wheel stays true longer and the spokes will have a longer fatigue life.
The tension conversion calculator is designed to work with Park Tool's spoke tension meter and is available to everyone at http://www.parktool.com/repair/calvinscorner.asp
When we perform a Pro Wheel Build at Freewheel Bike we tension balance the spokes and provide you with a copy of the final readings so that you can see how well your wheel turned out.