First of all, you're going to need an online collaboration tool -- an easy way to share documents (not code) that you all need. I frequently use Microsoft SharePoint for this, simply because it is included with Windows Server and is available in our company. There are lots of other tools out there, from enterprise level document management tools like Documentum to open source products like Drupal and Joomla. You can also use Google documents for this. You might want to look for tools that also provide shared calendars, contact lists, and to do lists.
You are also going to need instant messaging of some sort, preferably something that allows you to share desktops and video chat. AIM, ICQ and other free products can do this, but you might want to be mindful of any security risks they expose you to.
I have recently developed a liking for 37Signals, a company that provides Web-based group productivity tools that you can subscribe to. Their products include Basecamp, a project management and collaboration product Highrise, for contacts and simple CRM Backpack, for intranet, group calendars, and organizers and Campfire, real-time group chat for businesses. I use some of their products and like them very much. I highly recommend looking into this family of products. You can learn more about them, or even try them for free, at 37signals.com.
This was first published in March 2008