Do you know what software you're going to use on the website?
If you have little web development expierence you should consider using a CMS. Content Management System. Which will allow you to publish, edit, delete and manage content on your website. Some of the major players are Joomla, Drupal and PHPNuke. I would recommend wordpress. It's the simpliest to use of the lot and has a tonne and a half of helpfull plugins.
WordPress › Free Blog Tool and Weblog Platform WordPress Plugin Database
As for designing the site....there are 1000's of free templates available. If none of you have expierence with developing sites then you could easily get someone to skin/modify a wordpress theme for a small fee
Advertising wise you should look at phpadsnew
Welcome to phpAdsNew / Open-source ad server
It's a program you install on your website which can rotate between adverts. It's very powerful and easy to setup. It's got a handy plugin for vbulletin. (if you're going to install a forum of course)
phpAdsNew Banner Ads integration (advertisements, classified ads, Adsense, etc.) - vBulletin.org Forum
Finances
Since there is a group of you, ye should consider some sort of financial mangement system. You can install mysledger on your website in order to monitor your finances. You should also consider setting up a specific bank a/c and use direct debit from each of your a/c's to fund the site. This bank a/c will fund the site and will hopefully ensure that everyone is paying their way. It's very easy to fall out over money when there is a large group of people.
SQL-Ledger Accounting
Although using sql-ledger might be a bit of over kill...it's important that your finances are managed. Maybe someone else can recommend an alternative?