I'd like to start up the App Store from within my iphone app. Is this possible - and how?
Thanks.
I believe this URL prefix will launch it.
itms-apps://
Other apps also have URLs you can use to launch them. You can register your own as well.
http://www.mobileorchard.com/apple-approved-iphone-inter-process-communication/
As per this question on stackoverflow, it is not possible.
It may still be possible to communicate with a different app through a URL scheme, if that's what you want to do. Read about that in this answer.