Get listed on google

I'm sorry. I'm sorta confused by what you're asking. Do you mean that when you go to www.site.com your forum index appears? Or is your forum in a subdirectory at www.site.com/forum/

Don't worry though - changing your forum's directory path is easy to do, and doesn't require you to reinstall the forum software or lose any of your existing members or posts.

You can promote your forum directly... you don't need to move the forum or create a new index page for this.
I must tell I don't have any experience with IPB... I do now that vBulletin is better for search engines.
If your forum site is already indexed in Google moving the forum will be like starting from cero with them so I do not recommend doing this. In my experiencie even when you move it correctly and set all the 301 redirects and change all the links you will get reindexed and wait to see your site again in the search results.

Try promoting it, get valuable links and your site will eventually appear. Content is King!

You can promote your forum directly... you don't need to move the forum or create a new index page for this.
I must tell I don't have any experience with IPB... I do now that vBulletin is better for search engines.
If your forum site is already indexed in Google moving the forum will be like starting from cero with them so I do not recommend doing this. In my experiencie even when you move it correctly and set all the 301 redirects and change all the links you will get reindexed and wait to see your site again in the search results.

Try promoting it, get valuable links and your site will eventually appear. Content is King!

Thanks m8