There are a several different methods of scanning and depending on how big you want the final output to be, some are better choices than others.
Drum scans will give you the highest pixel density images (11000dpi). Commercial labs like
BWC have this equipment, but the cost for a single scan can be rather high. On the low end, you can get a whole roll of 3-4MP scans on a CD for less than the cost of single drum scan.
I have a Nikon Coolscan 5000 that is in the middle at 4000dpi. It gives me very nice results with both negatives and chromes. I have yet to scan a B&W image, but then again I don't shoot a ton of film.
I'd suggest you call BWC and ask them since they don't have a price list on the web site.
Good luck!