.htaccess help

So if I'm thinking correctly, what I'm trying to do should be accomplishable with a mod_rewrite in a .htaccess file.

There's a forum that I'm involved in that recently moved domains, though there's still alot of URLs all over the place (and on other sites) that still link to the old domain (which will no longer work).

So for example a topic that used to be at http://example-1.com/forum/index.php?topic=67.0 will now be at http://some-new-domain.com/index.php?topic=67.0.

would I be able to use a .htaccess file that redirects any request on the original domain over to the respective place at the new adress?

I'll take their request for example-1.com/forum/<*value> and send them to some-new-domain.com/<*value>

Sorry if my explanation of what I'm after sucks. I've done some menial searching for a guide or something but come up dry so far

Jam it back in, in the dark.