i use several. you might try our own Stroker's site. his 'lum frequencies' can be used for sharpening.
i also use 'sharpen' and '7 band sharpen' from AIM. these are both quite good.
and, paint shop pro's sharpening is pretty good, and though their usm kinda sucks, their 'digital camera noise removal' tool has a built in sharpen feature that when combined with the digi noise removal, can do some pretty nice things, easily rivaling Neat Image and others.
there are also ways to sharpen with contrast. and there are lots of programs out there with contrasting tools, some good, some not so good.
you can also sharpen with equalization and histogram adjustments to a certain extent.
and, for those really densely blurred images, you can sharpen or de-blur with programs like 'Unshake' or 'Focus Magic'.
also look for programs or plugins that advertise 'deconvolution'. these will often give you a better rendering.
and that's just some of what can be done and what's out there
craig