Good question and one i will be happy to answer! Nothing is more exciting than a new business venture (at least imo)

Ok, first establish who your target audience/market is? It's obviously people without hosting who can't for whatever reason afford a decent forum.

Now we know who we're looking for, we just need to find them!

The first thing that springs to mind for me is, a large popular free hosted message board called ezboard (i'm sure everyone has heard of this).

Various ways to attract attention...usually people who post on ezboards end up having their own one anyway! I suggest searching for the largest ezboard you can find....or the largest general chat one.

> E-mail the owners of the community and offer them your services, a FREE hosted forum with choice of skins instead of their slow and outdated ezboard!

> Find forums where you can advertise and post your offer or join large communities and use the sig trick to drum up interest.

Aside from that.....join vbulletin.com, phpbb.com and invisionpower.com and post in their forums with your advert in your sig. You need to spend about 2 hours a day..maybe more posting and advertising, it will pay off.

Join large forums like webhostingtalk, sitepoint, yaxay and use your weekly or monthly advert to good effect.

Google adwords, open an account and put about $100-500 into it, get terms like "free forums", "free forum hosting" etc.

I wouldn't waste money on advertising and i wouldn't really bother with targeted traffic and all that nonsense...your product isn't suited to it and the roi would probably be poor.

I reckon you can get about 100 forums hosted on a budget of $500 (just google, the rest is free!) And i reckon if you start your google campaign tommorow and get posting tonight.....you could start seeing the results in a few days.