I second what Fildy says. Also SNGWIZ is also very good, and factors in the possibility of multiple callers.
Also, Colin Moshman's book, and if you don't want to go to a different forum for advice, search back for some of my SNG theory posts.
Note: there are many more SNG pros with more experience than I at that other forum with the arithmetic name, but that zoo also has other issues that this one at least usually does not.
