Hi,
One thing I am not sure about is whether I still need my own SSL certificate if I use the services of a company such as Worldpay. I assume, that if I was to do the sales through their site that I would not need a certificate. However, if I integrate it into my site, would I need a certificate...
Thanks again.........

No, you don't need aN SSL with worldpay

However, if you are going to pass peoples info such as name, address etc to the WorldPay servers, some people may be happier entering this info via an SSL page on your site.

-- Chris