> I've just scanned in some old black & white photos - are there any
> freeware programs (or techniques) whereby they could be converted into
> colour?
You may want to check out Revelator Grayscale-to-Color
Also, B & W enhancement and color modifaction with e.g. this
Photoshop plug-in : virtualPhotographer http://optikvervelabs.com/
(e.g. IrfanView can work with this)