dacalio, whatever program you use, I highly recomend it be vector based or at least have vector output (EPS). Vector graphics will give you the capability of scaling the logo to just about any size without losing any quality. I use Adobe Illustrator for just about all of my logos.

If your going to use a raster based program (Photoshop), create it 300dpi. This will help you when you go to print the logo. Remember you can always scale the image down to 72dpi for the web.