How to simplify an iPhone share screen?

Question

After a user successfully performs an action - let's call it "Ramble" - I want to:

1. Prompt them to help their friends in the system do the same action
2. Encourage them to share (FB wall, Tweet, etc.) their action

I've quickly prepared (using Balsamiq) a rough draft which I don't really like:

Some of my concerns are:

• The screen is very cluttered
• The "continue" interaction/flow doesn't feel very "iPhone like"
• The social platforms might have been better served as checkbox style controls, but there's no room
• The confirmation of the action might go unnoticed

So any ideas on how to improve this page, or some examples of similar pages you've encountered and liked?

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Clarification
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There are two operations here:
1. Ramble for your friends (i.e. do the actual operation for them)
2. Share the fact that you Rambled yourself

Here's an updated design - let me know what you think:

Answer 1

How about just the one box that says share with a "mail" icon to share with friends:

(no apologies for ripping off your picture!).

When they select "m" they then get to choose which friends.

The big drawback with this is that if the links to Facebook, Twitter, LinkedIn etc. are already set up then those are one click actions while the "mail" is several.

Answer 2

Gowalla for Android (and Foursquare, I guess) use the following design:

The key here is that the status message of the app isn't duplicated, saving that entire form you included where you separately state that you just "rambled" something - why not just share the ramble itself? Twitter and Facebook are just checkboxes (which, in fact, still take up too much room in my opinion and are located in the wrong place, but whatever).

So that's one way of simplifying things. I think you need to look at your UI and not necessarily ask yourself how you can cram all that functionality in there, but perhaps if you should in the first place.