Overture bought AltaVista so for some keywords the top positions are sponsored links.
There is not that much info about AV at WebmasterWorld. Most of it is in the forum Paid Inclusion Engines and Topics [webmasterworld.com]. So to get in quickly you have to pay, but you can also submit 5 pages [addurl.altavista.com] per day for free in AltaVista. That last option will take some time (4 to 6 weeks). With enough links from other sites (especially ODP), you don't need to submit because AV will find your site automatically.
Some older threads about the AV's algo/ranking:
AltaVista Changes Ranking Algorithms [webmasterworld.com]
Ranking in Altavista [webmasterworld.com]
Lycos, MSN and AltaVista rankings - why should I care? [webmasterworld.com]
Some other threads about AV:
Altavista Launches New Look [webmasterworld.com]
Getting BACK into AV... - Should I care? [webmasterworld.com]
Hope this helps.