First, you will probably need an Internet "domain name". This is simply the "yahoo.com" or "spartacussystems.com" or "letsorganize.org" or whatever you are going to call your organizational presence on the Internet. An Internet domain name will cost you less than $15 per year to register.

Second, you need to have people and ideas.

You need people to help you with various tasks. If you don't have people to help, your odds of success drop radically.

You need lots of ideas:

You'll have to have an idea of what you want your web site to look like. Don't worry about the geeky stuff, think about how pages will be displayed, what links will link to where, and what sort of information you want to provide. (Some paper and a pen is real handy for doing this sort of work.)
Don't get wrapped up in details, think in terms of "flow" and how people will move around your site. Try also to be a bit flexible in terms of the actual look and feel.

A critical part of creating your Internet presence is to get people to use your site. Is your site locally-oriented or regional or national in scope? This will determine whether you can use flyers in laundromats and supermarkets -- i.e. local "advertising" concepts -- or whether you have to attract people already on the Internet. A great deal of thought should be given to how you are going to attract people to your site.

What "services" will you offer? Will you simply provide information via the Internet and then link to people via phone or non-Internet methods? Will you use e-mail mailing lists and make extensive use of e-mail? Will you use web-based forums for discussions? Again, what types of features will your Internet presence offer?

A huge, huge issue will revolve around transforming readers into activists. Use of the Internet is pretty much a passive or only slightly interactive medium, with people closer to couch potatoes than activists in the streets. Assuming that your objective is to do more than simply provide information, how can you convert those "couch potatoes" (for lack of a better description) into "activists"?

I'll be blunt -- the "work" (and also the energizing and "fun" stuff) is on you.

I'll handle the geeky stuff, provide facilities, and comments or suggestions (if you want), but let's face it: you have to make this happen and will determine your project's success or failure.