Forum Moderators: not2easy
Traditional copywriting techniques generally apply on the web so I'd consider buying a book on how to write advertising copy. Everyone here seems to have their own favourite.
As for SEO flavour, I've seen some links to ebooks floating around but haven't got around to reading them yet. Maybe someone that has can add their 2 pence.
Cheers,
Colin
I agree with Tigrou that books on advertising copy will offer great advice, probably a lot better than you might get from web-only resources. You may have to adapt a bit to the unique aspects of web marketing (e.g., "Buy Now" vs. "Click Here" vs. some other call to action). For e-commerce site copy writing, books on direct marketing are probably going to be the most relevant.
By the way, SEO and marketing copy don't always match up. SEO may impose some requirements on the copy that don't match the best marketing phrasing. With a little creativity, though, you can probably find an acceptable compromise.
writing for seo site:webmasterworld.com
There's a huge amount of stuff to look at. This is the first thread I checked, and there are lots of others:
Web Content and SEO
[webmasterworld.com...]