A successful wedding is as close as you smartphone.
Here are some helpful phone apps and web sites:
Wedding Budget (free at iTunes) helps you keep track of costs and if you turn your phone horizontally...Bam!...you get a pie chart.
Evernote.com (free; premium is $5 a month) is great for keeping track of everything as a sort of digital home, not to mention updating your friends and family. Also check out Awesome Note ($4 on iTunes; lite version is free) and Groups (free on iTunes).