You'll need a Google Account if wish to use the Members' Area or if you are to contribute articles to the web site. To simply use the web site (and receive email updates) you don't need a Google Account.
The club's web site is built upon a collection of Google components: principally Blogger, Feedburner, Calendar, Picasa and Groups. To play an active part in the Members' Area (a Google Group) you need to be known to Google, and that's where a Google Account comes in; it's a means of identifying yourself to Google, and you can use it across all Google systems. It's done by referring to your existing email ID - either your home email, or your work email, or some other email address.
If you're prompted to create a Google Account, just supply an existing email address as the Username, and choose a password (it doesn't have to be a password that you may already associate with the email address). Having done this you'll be prompted for a few more bits and bobs of information and then you'll be set.
Once you've got a Google Account you'll be surprised how many services Google supplies. The list includes Gmail, Picasa Web Albums, iGoogle (personalised search home page), and Buzz. You can use the same Google Account for all of these.