Pop up when clicking enter link

I'm looking to create some sort of "dual" link.  It will open a pop up window and then move the user onto the next site page.  For an example you could look at travelocity.com and enter information and choose "search flights".  It opens a pop-under that avoids the IE and Mozilla/Firefox pop-up blockers.  I want to do the same exact thing, except a pop-up instead of a pop-under.

For a futher description I have my homepage (index.html) and I want to have "enter" and "exit" text links.  On the "enter" link I would like a coding of some sort that will open a pop-up when clicked along with moving to the second site page (index2.html).

Thanks