You can, but it’s harder if you don’t catch them as they’re coming out… Any video rental store should have them by now though. (As well as hulu, like @dverhey says.)
Actually I just checked youtube and have found full eps… They’re split into parts of course, so I’d just make sure they’re all there before you start to watch one… Try searching “the L Word Season 1 Episode 1” or whatever ep you’re on, it’ll be easier that way.