How do I make pop up windows a custom size and position on the browser?

I basically want to link mini content pages, and put them in a small pop up box.

Thank you for your input.

I'm going to try to find that on Google, I'll report back if I find it :)

Well, do you want an actual new window, or do you want something boxlike that pops up and sits in front of the rest of the page's content, but isn't necessarily a new window? Either can be done (the latter is easier to position), but they are completely different JavaScript functions. Please elaborate :)