Printing invitations

[Pirate's Princess]

Has anyone used an online company to print their invites? If so, which company, and about how long did it take to do the printing. We're having someone design the invitation artwork for us, and we're planning on doing the wording on the back. I know it's not quite as formal, but it's fun and our style and I think it's going to be awesome. But the wedding is the end of October, and the artwork isn't quite perfect yet, and my mother insists that the invites get out in the mail by the second week of September. (which I know is the normal, but everyone has booked their stays already, it's no surprise as to what's coming).

Thank you!
(And for those of you who've noticed, sorry I've been MIA lately. I promise to catch up on everyone's pjs...eventually! )