After reading some posts on the subject, I came up with this really simple solution for adding a print page link to a skin:
<a class="printlink" target="window2" href="/default.aspx?tabid=<%= PortalSettings.ActiveTab.TabID %>&SkinSrc=[G]Skins\MySkin\PrinterFriendly&ContainerSrc=[G]Containers\MyContainer\PrinterFriendly">Print this page >
 <img id="" border="0" align="middle" src="<%= SkinPath %>printer_small.gif" alt="Print this page" title="Print this page" /></a>
It's pretty much self explanatory. You get the current TabID from <%= PortalSettings.ActiveTab.TabID %> and use this to form a URL that includes SkinSrc and ContainerSrc parameters. Point these parameters to your print friendly skin and container files (less the .ascx extension). Include a printer icon in the hyperlink if you so desire. Use [G] for a host skin and [L] for a site level skin.
Easy.