Most of the time I just use unsharp mask but I prefer several very light applications rather than a single heavier "hit". I think this provides a more natural result and it doesn't leave a horrible halo.
Last week I downloaded Intellisharpen from the Fred Miranda site
http://www.fredmiranda.com/shopping/IS and I'm very impressed by it. It's essentially a complicated set of actions that's automated into a Photoshop plugin. It's well worth a try.