Latest toy today is
M-x tags-search
I added the following to my .emacs file:
(global-set-key "\M-s" 'tags-search)
You also need to build a TAGS file, for my current work with haXe on the Orchive, I ran the following:
etags *hx
Now, to search for a tag I just need to go:
M-s
and then to repeat the tags search, I go:
M-,
Finding the definition of the tag doesn't seem to work with haXe, I'll play with it some more and will let you know if I figure it out.