any particular recomendations from those who have to have it done regularly? Mine is well overdue, and i'm hoping thats why ALL of my images have been soft lately (not to mention i'm not particularly fond with the black spots in my sky at f/7.1 or higher either).

best looking thing i've found so far is www.visibledust.com and its review at http://www.luminous-landscape.com/reviews/visible-dust.shtml