[postgis-users] Build polygons from points

[galen]

Say I have 500 points that represent an area and I'm hoping to build a 
polygon out of those points.  Is there a good function to do this in 
postgis or a good program that anyone has written that can accommodate 
this?  Obviously there is no "perfect" method of building polygons from 
points, but a function that accepted some inputs (like concavity 0-10 or 
something, similar to the way Simplify works?) would seemingly help me 
refine the "perfect' method for my purposes.

Thanks,
Galen