First of all VI stands for Visual (nothing visual about it) and VIM stands for visual improved.
Move cursor to the end of the file
:$
Move to the beginning of the file (1 stands for first line)
:1 or :0
Search and Replace (c Stand for confirmation)
:s/old_string/new_string/gc
Search for Words
:/string_to_locate
Page UP
CTRL + B
Page Down
CTRL + F
Useful Web sites
Vim book
http://www.truth.sk/vim/vimbook-OPL.pdf
Vi manual
:help