hey, I bought a domain, tetrisattack.org
and I was curious as to what you guys thought was the best forum software
a buddy of mine suggests invision free, but I was also curious about phpbb.
what do you guys think is a good piece of software?

I don't have much experience with invision, but I did fiddle around with phpbb one or two times.
At the very least, phpbb is a good choice because it is essentially a freeware version of vBulletin. So it isn't like your forumers will get confused.

I've been using phpbb over the last few years. Easy enough to use and extend, and I've found most forum users can jump in with no issues.

... and there's nothing more abused by spambots than phpBB

Another rather popular alternative, in addition to the ones mentioned, would be Simple Machinces forum. It's got a decent community around it, the security track record is not too bad either.
Or.. if you're feeling more adventurous and want to go with shiny web 2.0, esotalk is on offer. Haven't tried it myself, apart from the very basics, however..

I'd really like some more feed back.
I'm scared of the PHPBB stuff being spammy, any info on that?

PHPBB is good and versatile, you should be able to add a captcha thing or set up a manual process to approve users to help fight spammers. Also you could add common spam terms (especially involving converting video for ipods) to a list of filtered words so whilst it might be still spammed the urls will be mangled
I think vBulletin is the best forum software I've used but its not free

I like phpBB, and version 3 is pretty good against spambots if you just enable the built-in captcha (version 2 was terrible because it just used static images, so the same character always looked the same, v3 is random and thus much better - though of course there are still plugins/addons to make it even more so) and disable anonymous posting (though I think it's disabled by default).

Simple Machines Forums - SMF - Is awesome, I can only recommend it.
Used it for around 3 websites and communities so far and have not had any spamming or hacking problems. Not talking small websites either.
2177139 Posts in 79715 Topics by 22721 Members. =)
The only downside with it is that it is often hard to integrate hacks / mods. This is due to mods installing themselves into the default skins, but not any custom skins you may have, so if you use a custom look then you won't be able to easilly install mods ( it will require coding on your part ).
Also, if you install mods, it gets difficult to update the forum software since some files will have been changed, and if you are unlucky then the Mod-Author has not updated their mod for the new version.
So if you wanna dabble lots with skins and mods, then I can only recommend SMF if you have some PHP & MySQL knowledge.
Edit:
I should also add that, as a PHP developer, SMF is a joy to work with. You can very easilly use the forums as a global login system for your website, and then build parts of your website based on forums.
What I mean is, you can easilly make a group that has the ability to access restricted content on the forums, and then make websites that can only be accessed by this group in particular.
You can also easilly achieve to only let people on websites when they are logged in on the forums. So yeah, good stuff, really easy to build a CMS around SMF.

For the sake of being different, I'm going to suggest Vanilla. It's does things a little bit different, but it's better suited to small forums than many other forum software, imho.

Last time I hosted a forum, which was a good 5 years or so ago, I actually used my own code base. I've been coding an updated version on and off ever since, but I'm still not sure it'll ever see the light of day...
As for commercially available ones, I wouldn't suggest PHPBB unless they've seriously improved their security. I'd also suggest looking at Simple Machine's offering as I've seen it put to fairly good use by many an Indie developer =)

simple machine seems cool enough
http://tetrisattack.org/taforum/index.php