I need someone who can help me with price comparison web sites, such
as pricegrabber. lets say i want to buy an IPOD. Pricegrabber shows
multiple stores with the store's price for the ipod. How does
Pricegrabber get each stores price. Does the stores send their prices
to pricegrabber? How?//

There's some useful info here:

http://www.startupjournal.com/ideas/hitechonline/20041001-borzo.html

A merchant or seller who wishes to list their products with a
comparison shopping site like nextag.com would have to maintain and
upload a ?feed?

This ?feed? is usually just a excel spread sheet listing the merchants
prices, product description and a link to the merchants ?landing page?
(the URL to the site)

Of course, before you can list with one of these sites, you must agree
to the sites t.o.s and set fees for the referrals.

You can change your product?s prices by simply making changes to your
date feed, the changes will take effect on the site when the site
uploads your feed (usually once a day in most cases)