Firefox-like bookmarks?

I am new to WordPress, PHP, CSS, etc. I would like to create a content site. The key resource would be Firefox-like bookmarks, arranged in a tree or folder structure–collapsing/expanding. The leaf nodes would be links, either to my blog posts or to pages on other sites. As administrator, I could create links. Users would be able to use them, but not change or create them.

Ideally:
– new links could be created by drag and drop from a browser
– existing links could be imported from a file containing HTML, so I could kick the resource off with a subset of my current browser links, the HTML being in the same format that they are saved by XMarks.

I don’t want to reinvent the wheel if this is already available. If not, at what programming level can it most easily and effectively be done so that it could be incorporated into a WordPress-based site? Thanks.