Small Businesses and the Outsourcing of e-Commerce?

Zzzt asks: "I work at a very small advertising agency & production company, doing various electronic media projects, including small websites. In anticipation of our clients going elsewhere, my boss decided we should offer development services for commerce websites, complete with credit card transactions and the like. For those out there who have created these sites, is it worth it for a small company to take on such a project, considering maintanance, liability, and other issues that will come up? Or should we just outsource the whole thing? For a medium to low-end HTML programmer, are there pre-canned packages that will most of the work for me?"