Hmm... you could use something like www.faxaway.com.
1. your server returns Page X.
2. Page X includes a button "Get Hardcopy"
3. This button takes the WAP device to a page requesting a fax number
4. User submits that to an ASP page.
5. ASP sends an e-mail (with the content from Page X) to firstname.lastname@example.org
6. Faxaway's system automatically faxes the Page X content to the user.
BTW There's probably plenty more people doing the same thing as Faxaway but they were the first ones to come to mind.