Well here is one straight out of the OMG folder. I recently got a new filter for Adobe Photoshop works just as well in Corel so no fears there. It's called Andromeda Etchtone. You can read about it here (http://www.unleash.com/kurt/andromeda/index.asp).
Select any photograph, colour or otherwise, bump up the contrast and brightness, select Etchtone, alter the lines per inch to 300, choose extreme sharpening of 800,5 and click go. Result is a picture that is ready to send directly to the laser. Choose your recommended settings for wood/metal etc and that's it. No brainer and simple to use with an excellent result.
This is a picture of my neice Lucy, taken from a colour photograph doing exactly what I said above, only graphic work was to crop the photo. The whole 'processing' less than a minute from crop to laser. 12 mins to engrave at 300dpi 33 speed 100 power. Good result? I think it speaks for itself. This is on a mirror (our nightmare usually) but results on wood are just as tremendous.
With the new version of photograv coming out this is something that you should consider if you are on a tight budget. I was impressed.