Try plugging the cmyk values into the color palette in Photoshop and then select the pantone guide. It should come up with the closest PMS color.

That's it! Thanks, Ken. I was trying to do this in Illustrator with no luck.

"Try plugging the cmyk values into the color palette in Photoshop and then select the pantone guide"
This works sometimes...This direct convertion dont work almost everytime. And if the logo is to be printed them Its really a problem. The cmyk values must be corrected manually. If not you will have a diferent color! I have that experince in pantone 179 (a dark red) that converted directly to cmyk results in printed page orange!
This is really an issue!
So the best way is to ask to the print house a catalogue with cmyk values and them convert manually to the best value (eg that matches best with your pantone number).

António

Get your hands on a Pantone Color Bridge and see the CMYK and Pantone equivalents side by side. Then you can see how similar/different the different colors are. Find someone who has this swatch book and borrow it to find this out. You might have to shell out for one, but it's worth it later on.

You're welcome, Patty. Obviously you'll want to check it against a swatchbook as others have noted.

Yes, I have checked it using the Color Bridge - which I agree is a great investment. The problem was I didn't have a printed piece to reference for color so rather than just guestimate I wanted a starting point.

I was just doing this as a favor for a friend, so whether or not the colors match exactly is kinda not really my problem. I gave her the disclaimer that there you never get an exact match between spot color and process. But even if the color's off it will look better in 2C spot than 4C.

Thanks again, all.