New to e-commerce advice wanted!

Hi,

I am a student web developer and I have been approached by a client and requested to build an e-commerce website to take their business from an e-bay only shop to a fully functional e-commerce website.

As i have never built an e-commerce site before I am reluctant to take this project on despite the great experience it could give me.

I recognise the fact that I will need to expand my skill into this area for future projects so what I am asking is how to go about building an e-commerce site? Should I be looking to write everything myself or are there good frameworks you can add in that have the shopping cart, billing and payment feature built in?

Any help or information would be greatly appreciated.

Thanks in advance,

Phil Reeve