Below are a handful of companies (existing or not) that license anime in the United States. The shows that I'll review will belong to at least one of these companies. They're also be links to these sights, although some of them are in Japanese (with no "English translation" button).
ADV Films (R.I.P.)
http://www.advfilms.com/
Funimation
http://www.funimation.com/
Media Blasters
http://www.media-blasters.com/
Pioneer
http://www.geneon-ent.co.jp/rondorobe/
Gainax
http://www.gainax.co.jp/
Crunchyroll
http://www.crunchyroll.com/