Hi Rw,
I haven't seen it mentioned here, so I'll tell ya about a method I use to get some pretty high-PR links..
Hopefully you're using FireFox, and if not then for this you'll have to get it. If you download the add-on "SEO for FireFox" and install it, every time you Google Search something it will give you tons of info under every result, including their backlinks and the exact page they're coming from.
There are tabs for Page links, .gov backlinks, .edu backlinks, and more... I use this to pick off authority links (like .gov and .edu), and most times all you need is a few .edu or a couple .gov links and you're pretty much good.
This is way easier than using other services, and you can rank for your actual product pages really quick, like within a day or two (since they're longer-tailed keywords...assuming this is the kind of store you're operating).
There's software and all that does this too I assume, but this is free and easy. It's really straight-forward too. If you need any help with it, just let me know. I'll try to find the link to SEO for FireFox if you need it as well.
Hope that helps,
-Tom

