DEF CON  see you there...
Hacktic the ancient gods
Phrack the uberultimate lots of good old philez. (greetz)
nettwerked clone at his best.
Hacktic (former link was l0rd's page..) hacktic
  2600 cool magazine on phreaking/HPA
  hackcanada the coolest hackers in the world
telephone tribute AMAZING..
phonetrips very nice documented oldsk00l phone/switch tunes!
  Secureroot awesome site on security links, now kinda dead argentinian security site some  old (97) files
  ccc Chaos Computer Club Germany (former twpyhr)
great site for phreaks and phone addicts
  telecom security task force
shitty flash/sound webpage, but they had the first sctp scan tool!! 
art of hacking "uber the website you already know anyways.. love it. some nice files on asterisk, phreaking, hacking
joe engressia  r.i.p. the inventor of hanging up by whistling a tone...
(i can confirm it worked on swiss networks,
 but whistling 3kHz (r2) was hard..
but possible;) ..before all became ss7)
link to the esquire reporters blog
  cap'n crunch no phreakerpage without him, whatsoever ;) 
Phreak philes
YIPL (TAP) at the beginning..
bioc agent 003's telecoms series bioc agent's philes
phreakvids some vids on phreaking
  The Anarchist's Cookbook  good to know but not recommended
Telecom/IT Organisations    
  ITU International Telecommunications Union
Documents on SS7, R1, R2, C5 etc
available on Dowloads or on CDrom, quite expensive...
  ETSI All info on GSM and UMTS for free !!
  IEEE The Institute of Electrical and Electronics Engineers
OMA all on wap/mms necessary things
  Using GPRS with linux  some good info on using gprs

UMTS security

  Free SMS to UK phones (CBFSMS)
 (they took the old ..)
 send anonymous sms
Sigtran guess no chance to beat wikipedia, so heres the link.
this is whats goin on, so check it out!
CDMA cdma dev group
ifast ANSI-41 standards us (gsm sortof) stuff

International Chipcards  nice collections of cards
  silvercards  this might be handy one day..
  Telecommunications Online -- May 1998  
  GSM List  
   LOTS of info and a phree book!  Ross Anderson / Cambridge
Federal Offices    
  NSA National Security Agency
E-OFCOM (BAKOM info site)
Bundesamt fuer Kommunikation

Go here to get all info on International Signalling Point Codes (ISPC)
(select allocated  codes, parameter list)
Go here for carrier selection codes
Reverse Engineering    
   ERESI  i just like this kinda stuff;)
Cool pages, phone related    
   Payphone Project  nice collection on public phone pics
 phone interception