For-Pay Streaming Sites
Amazon.com Instant Video
Amazon's video service is pay-only, but offers both the ability to watch shows online or download to own. Season sets of episodes are available at a discount, too. Among the shows available: "Naruto" (uncut), all 11 seasons of "Bleach" (dubbed), "Fullmetal Alchemist", "Kino's Journey", "Star Blazers", and many more.
Apple's video and music store sports a fair share of anime titles from VIZ and FUNimation, although they're copy-protected as all iTunes video is, and requires the iTunes software to be accessible.
The premier rent-by-mail video service has a whole "Anime and Animation" subcategory, with many popular shows and movies available both for rental and for streaming.
Available only through the PlayStation 3 (via the PlayStation Network), Neon Alley offers HD streams of English-dubbed anime from the Viz library (Naruto, Bleach, Blue Exorcist, et al.) for $6.99 a month.
Microsoft's online video store has an extremely broad range of shows, in both standard-def and HD. Many are FUNimation and VIZ titles, but titles from other licensors appear, too: "Ghost in the Shell: Stand Alone Complex" (Manga/Bandai) and "Blade of the Immortal" (Media Blasters). Note that this store is for owners of XBOX devices only.