Vim and C code

[Martin Vana]

Hi,
I would like to do some more advanced editing of my C programs in Vim,
like to go through program step by step or to have 'watch' on some of
variables. All I've achieved now is syntax highlighting and Quickfix with
:make command. I know there is EMACS somewhere out there, and
other more complex enviroments, but I would like to stay with Vim, which
I presonally like.
A link to some tutorial would be exactly what I need.
Thanx

PS: A bonus questions for those who haven't answered any newbie question
yet: I can't get :s/aaa/bbb/g to be working from curosor till the end of
file only.