| Typically, on a four string bass:
Set the G string saddle so the distance from the center of the saddle to the 12 fret is exactly half the scale length. In other words, for a 34" scale bass, set the G string saddle so the center of its circumference (assuming it is round) is 17 inches from the 12th fret.
Set the saddle distance of each progressively larger string (D, A & E) further away from the 12th fret by a distance approximately equal to the size of the string itself. In other words, if the D string is a .065, pull the saddle for that string .065 back from where the G saddle was set. Repeat for the remaining A & E string saddles.
In the end, the array will be staggered, with the E string being the furthest away from the 12th fret.
You may (probably) need to make some minor adjustments to the actual saddle locations when you check/set the intonation, but this method will get you in the ballpark (usually).
It probably sounds more difficult than it actually is, due to my lame-ass description of it. | 
