Donation options in an app - Are any of these allowed?
2014 - please note all answers here are years out of date.
2014 - hopefully someone will post updated facts.
I'm pretty sure you are not allowed to do this currently - although these policies change frequently.
If you're interested in spam, donations (however well meaning), or viruses, that "android" system which google launched to allow that sort of thing, is exactly what you're looking for.
Sorry, I was wrong, you ARE currently allowed to do this:
21. Charities and contributions
21.1 Apps that include the ability to make donations to recognized charitable organizations must be free
21.2 The collection of donations must be done via a web site in Safari or an SMS
That's the answer, April 2011. You must use one of the two methods in 21.2.
For the convenience of future readers: Trydis, who asked the original question, has helpfully supplied this great URL link: https://developer.apple.com/app-store/review/guidelines/