Looking through my mails I found this really informational message from Kcid.
Posting it as an article.
2005.10.04 18:43:00
Security status, or lack thereof, can
have a big impact on your ability to
travel through the EVE universe.
Here is a brief list of your travelling
options according to security status:
Players with -1.5 or greater can
enter all systems
Players with -2.0 or worse cannot
enter 1.0 systems
Players with -2.5 or worse cannot
enter 0.9 systems
Players with -3.0 or worse cannot
enter 0.8 systems
Players with -3.5 or worse cannot
enter 0.7 systems
Players with -4.0 or worse cannot
enter 0.6 systems
Players with -4.5 or worse cannot
enter 0.5 systems