I'd agree that the Wilton wedding cake book and the Cake Bible are both good resources. Wilton puts out new books every year so you can get a huge variety of styles.
There's also a good thread that was started a long time ago on wedding cakes. I'll try to find it for you and bump it up.
If you need to order materials and such, www.kitchengifts.com
is where I used to order all of my decorating supplies. (ahhh, the good old days!
You're such a nice sister!!!