I think one of the woodworking magazines did a review of cleaners or rust-preventors a couple of years ago. Might have been Wood or Fine Woodworking. Don't remember exactly what they found but I seem to recall that most of the products were pretty useless and the ones that did anything were expensive.
For cleaning saw blades and router bits, Simple Green is often recommended on wood working forums. Just be careful with this stuff: if you use it full strength, it may cause the metal to pit if it's in contact for long enough! I wipe down steel an aluminum with Simple Green before welding and can attest to the fact that it does a pretty good job of cleaning up general grease, oil, and gunk!
Hand planes and chisels I wipe down with camelia oil to keep them from rusing. I got a small bottle for free with some purchase or another. Can't really tell that it does much good, though.
To be honest, I clean my tools and blades at the first sign that they're getting dirty so I'm not sure what you'd use if you have a blade that's really caked with gunk...