Some will charge by the gig and others will charge by the hour, and it's not cheap. I know some london drugs will do it.
http://www.actionfront.com/a_londondrugs.aspx
http://www.datarecoverypro.com/?gcli...FRo-awodqCzadw
Hopefully someone else can chime in here and give some personal experiences. I've done all my own at home and have never had the need to use a professional service so I cannot really comment on which company might be best to go with.
A few things to keep in mind though, ask for references if you aren't sure (just like you would ask a contractor). Also check their rates (duh) and their guarantees as well.