Passing Post ID to a custom page

Hi, I’m pretty new to WordPress and I’ve been searching for a while now…I’m trying to figure out how to pass a post_name or post_id via a link to a pop-up window. I want the window to allow users to send the post to there friends in a simple manner through several fields, while including some information about the post besides just the permalink.

What I need help with: What would the pretty link be for opening a page “email_friend.php” for a post “21” or a post titled “Garble-garble”? I realize the format might change depending on how I have those set up as well, and that I probably have to register this page in the WP Admin panel with a custom template

…or maybe another way to achieve this would be to take the single.php page and place an if statement within it to tell it to look for a variable in the link telling it to show the summary and email forms. But how would I reference this variable in my code?

…I’ve been working on the template for such a page, but I’m lost on how to link to this page via these “purdy links” in order to create a dynamic page.

Thanks for the help!

p.s. …also just realized this is probably in the wrong forum, sorry : )