Mount Manager is probably a bit obsolete now. The ability to mount remote volumes has now been neatly incorporated into recent upgrades of MacOS X. Its still available for those who want to try it out, or for those using 10.2 or 10.3, but I won't update it or actively support it anymore. You can check the FAQ page if you have any problems using it.
Mount Manager is a MacOS X utility which allows you to mount network shares with a single click of a mouse. Shares can be set to mount when Mount Manager launches, and with Mount Manager as a startup item, you can have your favorite shares mount when you log in.