As mentioned in the description for the last link, there are a lot of Robin Hood pages on TV Tropes, but here is the character page specifically for the BBC series.
The TV Tropes page for the series. Note that the links at the top of the page are not all necessarily associated with this series (some point to various movie adaptations of Robin Hood).
The official (albeit currently inactive) mini-site for the series. Does still contain some helpful information on individual episodes, and where to find them.
A great little tumblr full of fun graphics and quotes from the series. Probably a good source of reaction images! Worth following if you haven't already.