We have two dogs, a Jack Russell and a Mini Schnauzer, they get walked all over the place, the beach, woods, fields, they roll in all sorts of revolting things (well, the Schnauzer does), and as a result their beds get pretty filthy. I put them through the wash fairly frequently but they come out still smelling doggy. I read a thread on Good Housekeeping about washing with white vinegar in the fabric softener compartment (as well as normal washing powder / liquid), so I tried it with the dog beds today. They smell fantastic! Not a trace of dog smell, I am so pleased! The dogs, less so. They like their beds stinky.
Of course, you may all have been doing this for years, but just thought I'd share, as it was a revelation to me!