I haven't tried any of these myself, but here is a handy list of some of the top rated wedding related apps. for the iPhone and iPod Touch.  Let me know if you like any of these.  Enjoy...

iWedding Deluxe - a wedding planner and organizer

Bride's Dressing Room - digital shopping concierge for brides on the go

Bridal Sugar - chat with other brides, exchange ideas, ask questions

Toast To Toast - afraid of what the best man might say?  Let him read from this app.

Wedding Date - a countdown app.

Beauty Care - choose the nearest Boutique, Day Spa, Hair & Nail Salon, Health Club

Wedding Clink - don't let the guest ruin all the good silver ware

Wedding Videos - video tips for your big day

Wedding Games - Wedding games and activities guide

Lovopoly - classic board game with a romantic twist