Being that I work in and support a graphic arts department, color calibration and color management are issues constantly on my mind. There are very good tools on the market to address these issues however, and as another industry buddy just asked for a rundown on my experiences, I figured I’d do one here.
There are many tools on the market, starting at under $1000 for a package of both screen and CMYK printer profiling tools. Here are the ones I have experience with:
ColorVision Spyder2PRO
A best-seller in this class is the ColorVision Spyder2PRO Suite. This was the first road I went down on my way to a working solution. The Spyder2PRO USB monitor profiling setup was adequate, but not great, at matching screen colors to Epson color proofs. The ColorSavvy ColorMouse CM2C, the printer profiling setup, was almost completely useless. It is a setup that uses an RS-232 to USB adapter, and if you have ever tried to use one, you know how poorly they perform. I was only once able to actually get the device to interface with my computer and read a printout. Also, the ColorMouse only comes with very poorly executed software. I recommend against the ColorMouse. The Spyder2PRO is a fairly good entry-level monitor profiling setup , and can be purchased separately from the aforementioned package at a price of around $250.
Gretag MacBeth Eye-One
Gretag MacBeth makes the good stuff. The price of entry is higher, but as I have found, there is no substitute. The second you fire up the software, you know you are working with a competent hardware/software package.
I received an Eye-One Display 2 as a free gift for attending a seminar called Color Without Limits. This was an incredibly eye-opening class, and I would recommend it to anyone thinking of implementing a color-management solution, whether you are a photographer, designer, or printer. The Eye-one showed amazing results right off the bat. The colors the screens in my shop produced after Eye-One calibration were quite different than before, when the only color setup was done by our eyes and Adobe Gamma. At first it seemed strange that there was so much difference, until we sent our first few pieces out for color proofs. Amazingly, the printed pieces looked like what we expected from the color work we did on our respective machines. All the designers were stoked on the accuracy we were seeing.
At this time, we were going with accurate color on the monitors, and just dealing with the outputs our Canon Color imageRunner C2050 was giving us, since there was no RIP (Raster Image Processor) attached to that machine. A couple of months ago, we upgraded to the Canon Color imageRunner C3220 with the ImagePASS C1 RIP. Included in this package was an EFI- (Electronics For Imaging, the makers of the Fiery RIP) branded color-profiler package, including a device that is called the EFI ES-1000. The EFI ES-1000 is closely modeled after(and almost identical to) the Gretag MacBeth Eye-One UV Cut, a device for calibrating monitors, printers, scanners, cameras, projectors, etc.
Finally, all parts were falling into place. The ES-1000 provided monitor calibration right in line with the Eye-One Display2 I had been using to calibrate the monitors (since they’re made by the same company, they damn well should be similar). It also is able to read the printer output patches (you print a file with a ton of little squares of color, then hold the ES-1000 over it and it measures the ink densities of the squares), where it interprets how the printer puts ink to paper, and builds an ICC color profile to compensate for how the printer produces color. After building a profile, you can load it into Adobe Photoshop, or any ICC-compliant software, so that the files are separated based on the printer’s ability to reproduce color, basically translating color standards into data that the printer can use to output those standardized colors. Yeah, real basic. 
All that garbage I just said about printer profiles boils down to this - this product, used correctly, makes color look the same on your screen as it does coming out of your CMYK printer.
I know, there’s a bunch of confusing language and terms in this color-management stuff, but really, it’s far simpler than it seems. If you are looking to implement a color-management scheme in your shop, look to Gretag MacBeth for the hardware and software to get the job done right. And attend their seminar I mentioned above. The course materials and lecture will do wonders for your understanding of the processes involved.
