A selection of linls...

VTK Productions on the web:

Facebook Page
Vimeo Profile
Twitter Profile
YouTube Channel

Well known useful sites:

Vimeo
The best video sharing site on the internet! If you're a filmmaker I encourage you to join.

Withoutabox
Thousands of film festivals available to submit to through this site. Free.

Wikipedia
Who needs film school when you have all the knowledge of the world at your fingertips...

IMDb
The Internet Movie Database...

IMSDb
The Internet Movie Script Database...

Blogs and online magazines:

CeativeCow
Magazine, news, forums... for creative people.

Philip Boom
Blogs about new tech and DSLR filmmaking.

Den of Geek
Latest film and cult cinema news.

EOSHD
Mostly DSLR filmmaking.

Nofilmschool.com
A blog for those that never went to filmschool, but if you did - still a great read.

DVInfo.net
Latest news, forums, etc.

FreshDV
Again - latest news, forums, etc.

Forums:

HV20
Originally created for the Canon HV20, now covers everything.

Cinema5D
Disucssions on DSLR filmmaking (Canon 5D, 7D, t2i/550d etc...).

DVXUser
Mostly everything about filmmaking...

Filmmaking.net
Nice compact resource.