If I use 2checkout or paysystems, etc., what else do i need to have and also what do i need to make sure that my host has. e.i. SSL




All help greatly appreciated.

You will not need SSL if you are using a thire party merchant such as 2checkout, paysystems, paypal etc as they use their secure order forms for your orders.

You would only need an SSL certificate if you were going to use a merchant account and process all the sales yourself as opposed to having a third party merchant do it for you.

a billing program would be nice like modernbill

They will do all the payment side of things for you on there own secure order forms. You will need to think about keeping customer records.

Some CP have integrated billing, for example: ***+com+plete, Helm, Hsphere...

Whats "***+com+plete" ?

Although its nice for a control panel to have billing integrated, I personally wouldnt risk it.

I think its better to keep billing/support seperate from the actual server incase of downtime or technical problems.

http://www.clientexec.com/ is coming along nicely :)