Snapfish is an online photo printing service. Quite simply, you upload your photos to the Snapfish site, choose your print options, and pay with a credit card. Your photos arrive in the mail a few days later.
It’s simple and powerful. There are similar sites, like SmugMug, but Snapfish is one of the cheapest and simplest. The site also provides basic photo editing tools (red-eye reduction, tweaking colors, cropping photos, etc.).
You can get your photos as regular prints, as well as posters, photo books, calendars, mugs, etc.
Overall, it’s a really solid service. Highly recommended.