The Service Pack 2 update to Windows XP includes a built-in pop-up blocker for Internet Explorer. This tool stops unwanted Internet pop-ups from cluttering your screen, but can also block pop-ups that you do want. You can turn off the Internet Explorer pop-up blocker for specific web sites on a case-by-case basis in order to see thise pop-ups. Whenever IE blocks a pop-up, a bar appears at the top of the web page, similar to:

If you want to see pop-ups for this site (in the example, www.usatoday.com), click on the yellow bar. A menu will appear with several options. If you choose the option "Temporarily Allow Pop-ups" then pop-ups will appear for this site, but only for your current web session.  If you choose the option "Always Allow Pop-ups from this site..." then you will always see pop-ups for this site.

You can further manage the IE pop-up blocker by clicking on the "Tools" menu, and select "Pop-up Blocker". This menu has an option to turn off the pop-up blocker. If you select the option "Pop-up Blocker Settings" you can have fine control over the pop-up blocker, including adding or removing specific sites to allow pop-ups.