This is information I will probably need later. Though it will probably be useless to 99% of readers who stumble upon it, one percent might find it useful, thus it will be posted publicly.
For those who browse Apple's webstore at http://store.apple.com may have discovered if they try to send a link to a product page to a friend, the link expires after a while. Those are session links, and Apple probably uses them to keep people from buy products that no longer exist -- it also makes people have to enter the store from the front page. But you can work around this.
Links to specific items can be had by using http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore?productLearnMore= as the base link and filling in the product number used by Apple after the "productLearnMore=" argument. What is the product number? Generally, in the URLs Apple presents after you click on the item, the final argument (whatever appears after the last equal sign in the URL) is the product number... In fact the final argument is typically "nplm=[product number]". (Note: '%2F' anywhere in the URL is equivalent to the '/' character. Thus something that reads "MA222Z%2FA" is equivalent to "MA222Z/A".) This trick doesn't work on things which can be altered and configured (like computers), but you can easily get to those links from http://www.apple.com/hardware/ .
Here's a link in action -- right now, Apple is selling a 24" iMac refurbished for $1700, which I think is a better deal than the $2000 they ask for it new. The link to it is http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore?productLearnMore=FA456LL/A (for as long as it remains available -- refurbs go quickly).