Screenshot
About
Stack Exchange Deleted Question Viewer is a user script which allows any users with at least 500 reputation to see most deleted posts, if they have a link to them. If you have a link to a question, you will only be able to see the question, none of the answers. If you have a link to a specific answer, you will be able to see the question and that answer.
This will fail for locked questions, but should work for all others. It will display the post's title, content, vote counts and comments. If the post has been edited at least once, it will also display the author and editor.
You can try this out with a deleted question and answer of mine on meta.stackoverflow.com, then consider taking a look at the Popular Deleted Questions list on meta.
This script relies on certain bugs and design features that are likely to be changed at some point. I'll accommodate these changes if it's possible, but it may not be.
License
Released under the MIT Open Source License.
Installation
Click here to install Stack Exchange Deleted Question Viewer.
Platform
This is developed for Google Chrome. It should also work on Mozilla Firefox with the Greasemonkey extension, but it's currently untested.
Contact
Stack Exchange Deleted Question Viewer was written me, Jeremy Banks. You can just leave feedback in the comments, but if you would like to email me my address is in my profile.
Code
Stack Exchange Deleted Question Viewer was written in CoffeeScript. The source file is available here.
Oh, and...
...if any Stack Exchange folks would prefer that this be deleted, I won't object.