info about satellites

Hi everybody,
maybe my questions are OT, but I hope someone can help me.
I started intersting about satellites a few time ago, so
there are many things I would like to know.
I use Orbitron (an excellent program, in my opinion) to know
when and where satellites are.
But I would like to know info about satellites. Does anyone
know where to find them?
For example, there are satellites as satcom5, which have a
ground track shaped like a eight (8), changing his latitude,
but keeping its longitude. Why??? A geostationary satellite
must stay "fixed" in the sky (I think...). And how can a
satellite have this track? (the same for skynet4 or gstar3).

Or there are satellites which oscillate around equator, but
"go" along the equator, from east to west, and in some days,
make a round trip around the Earth.

These are the questions. I tried to search in internet, but
there are too infos!!!
I don't want answer here (I know I am some OT) but I'd
appreciate some links!!

Thaks to all
--
No SPAZIO to answer
Il vantaggio di essere intelligente è che si può sempre fare
l'imbecille, mentre il contrario è del tutto impossibile.
(W.A.)