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