4D - a possible forth physical dimension! :>

1- Here is a nice introduction to relativity
http://www.physicsguy.com/ftl/
especially nice diagrams (for example check: http://www.physicsguy.com/ftl/html/FTL_part1.html#di:film2st)

2- for the idea that you are looking at a 4D object from different angles:
http://alem3d.obidos.org/en/cuberot/ and http://alem3d.obidos.org/en/cubeice/

3- instead of reading the whole rocker book The Forth Dimension, take a look at this http://128.143.168.25/classes/200R/Projects/fall_1999/fourdim/home.html
it is basically a scanning and presentation of the main ideas of the first chapters :)

Other (less relevant) stuff
- an article discussing how you could kill your own grandfather :]
http://www.brown.edu/Students/Catalyst/pre2001/archive/fall97/time.html

- List of movies about time travel:
http://www.cvil.wustl.edu/~gary/SF/time_movies.html

- "... a site devoted to exploring the themes of time travel and alternate universes in books, film, television, and pop culture in general."
http://www.timetravelreviews.com/default.htm

- Time travel in Flatland?
http://www.theory.caltech.edu/people/patricia/lctoc.html

- "Temporal Anomalies in Time Travel Movies
unravels
Problems in Time" at http://www.mjyoung.net/time/index.htm

- Computer games and Time Travel:
http://www.localcolorart.com/search/encyclopedia/Time_travel/#Computer_games

- Great index of links on the subject:
http://www.localcolorart.com/search/encyclopedia/Time_travel/