I'm posting a heartfelt testimonial to the wonderful people at
www.slides.com .
Due to sloth, gluttony, and who knows what else of the Seven Deadly Sins, I was recently late in getting slides out and making a deadline. To make matters worse I didn't opt for the super-fast shipment. (That one would have been 'greed'.)
The compassionate slides.com people stepped in and saved my neck. I received a duplicate order so quickly it made my head spin. They are fantastic!
Not expensive, either. Each original slide is $4.00; an extra one is $2.00 and I think the price eventually drops to $1.00 for multiples.
I upload my tifs and I'll never go back to shooting film for slides again. (I see they also offer a Powerpoint service, though I haven't tried this yet.)