If you wanna know how much of a manga has been scanlated you should use mangaupdates.com. In the case of
Hell Hell, yeah there's 5 volumes but only one chapter was scanlated and it's not licensed in English either.
As for comics, there aren't any websites where you can read them online like there are for manga. The best way to go is to torrent them. You can also use
comic masterposts on LJ to download things. They're usually in cbr/cbz format so you'll have to get a comic reader (google it) too.