Separate site as subdomain?

[Fairyglass]

I have a site where we offer some stock only at retail and some also available as wholesale. I'd like to be able to set up a wholesale sub-site as part of the main site, with a log in. So I'd have www.mysite.com as the store front and retail store, accessible to all, and wholesale.mysite.com as a separately functioning shop (with separate cart) accessible only to wholesale customers with a password.
Can this be done, and how do I go about setting up the sub domain? I'm guessing a lot will depend on my hosting, which I have full access to, but I'd welcome any advice.
Thanks!

[pinbrook]

subdomains work in exactly the same way as whole domains ie separate copy of actinic, separate cgi-bin (or same cgi bin using different number), separate checkout etc

just use wholesale.domain.co.uk as URL instead of domain.co.uk, then test email/SMTP - it is host dependant on whether you can use @wholesale.domain.co.uk or domain.co.uk