Grep-Envy
Grep is one of those programs that's been around forever as a part of *NIX. Its function is straightforward. Grep:
searches one or more input files for lines containing a match to a specified pattern. By default, grep prints the matching lines.
In other words, grep is a super-utility for finding information inside any file on your computer. The fact that grep uses regular expressions makes it even more useful. "Regex" is like wildcards on steroids: for example, let's say you're looking for all telephone numbers in the (212) area code stored anywhere on your computer. With wildcard searching, you could specify a search that might get most of those instances, but with regular expressions (and a little practice) you can probably catch every instance of the numbers "212" linked with a sequence of seven other digits in a telephone number, while ruling out instances of "212" occuring in some other sequence.
Anyway, a lot of that function can now be had with Google Desktop. But even so, full grep function has been missing from Windows from the beginning--and people have tried to implement grep for Windows (Google search) over and over, over the years.
There's GNU Grep for Windows, part of the GnuWin32 package of ports of key GNU utilities for Windows (up through Vista).
There's the shareware/trialware Windows Grep that you can try out for 30 days/buy for $30.
There's even a super-duper GUI-front-end PowerGREP, for the bargain price of $149/single user license.
And did you check that Google search? With over two million hits, I'm pretty sure there are other implementations you can buy. Or, you can just install Linux--grep is in there, for free.