Matt,

Don't go deep in to Twitter if you will be talking to the "ether".

My first instinct would be to find out where your members are, meaning the ones that ARE using social media technology. My first thought is "are these non computer people on Facebook?" Even my mom, who is not computer savvy, is still on Facebook. Facebook and other social media outlets are "aging up".

I look forward to seeing what others have to say and see what they have tried to reach this non savvy audience.

I suggest hosting an educational webinar to teach them how to use some of the tools. You can make it very basic and go over the step-by-step instructions on how to use each tool. When you talk to them about the new media tools, use terminology that they are comfortable with. Talk about communication and networking. Don't talk in bits and bytes - sometimes this is easier said than done.
It is also helpful to have people onsite at your meeting to help attendees that want to engage with social media use the tools that you have set up for them.

I'd go hands-on at the conference itself, if you can't beforehand, and provide stations near registration or some other central gathering point that would have some computers and people available to help show folks how to create a flickr account and upload digital photos, tweet, whatever else you want to introduce. Maybe have your keynote speaker and a few (seeded if need be) audience members interact via SM tools during the session, just to show that it's really not so hard. It sounds intimidating until you actually do it and see how easy and fun it can be.

As Tony says, I'd also find out where the members who are already using SM are hanging out and go hang out there with them. Facebook seems to be the biggest winner with most people these days, though LinkedIn could be better for a super business-oriented group. Twitter, seems like people either love it or hate it. I wouldn't start with it, just because those who didn't grow up in a chat world world can find it confusing and hard to follow the conversation.

I know a lot of organizations have tried using proprietary social networks just for their conferences, but have found low usage if their people are already on a bunch of other sites. If your people aren't, they might be more amenable to giving it a try.

Appeal to their logical self-interest! Show them how internet marketing broadly and social networking specifically is changing buyer behavior (think about the last time you bought something - even B2B). As such customer acquisition and retention is changing, which means companies which do not innovate their go-to-market strategy will struggle to remain relevant! Look at the major newspapers, look at manufacturers and the changing dynamics of wholesalers and distributors. Even industries like executive education and insurance are learning "retail" techniques because employers are passing the decision, the burden, the choice, etc. to the end consumer of these and many other services.