I don't know how its called but I noticed several sites are doing this... is this white hat seo stuff? not sure... so basically there is a domain student-forum.org - redirects to -> forum.cheapbooks.com/ they have several other domains pointing to forum.cheapbooks.com/ also. is this allowed? can I do this?
Yes, you can do that, but I am not sure it will have much effect. They should have a landing page for each domain that allows the user to direct themselves back to the target site through a link. Otherwise Google will eventually figure out that the two domains have identical content and one will get smacked down. Or even worse, every few days they will bounce each outher out of the SERPs