Plenty of buzz in the last few days about iPhone being a
"no show" 
at MacWorld. This is not just from bloggers but also from some respected Street analysts who may have more insights.
One rationale for
no "phone show"

tomorrow (SJ Keynote) is that there has not
yet been an FCC application (required for cellular in the USA). Makes sense, but that would not preclude a launch in other world markets ... wherein, incidentally, Apple owns the iPhone name.
One more potential reason for "no show" tomorrow is Apple's behind the scenes work to build MVNO service/support. This will take some time.
My probability SWAG on timing of iPhone appearance ...
98% = iPhone ONE (simple/sleek iPod/VoIP/Cell) at least
discussed by SJ at MacWorld tomorrow!
50% =iPhone ONE displayed
"show and tell" at MacWorld
30% = iPhone ONE ready for
distribution in the USA by end of week
50% = iPhone ONE ready for
distribution abroad (many world markets) by end of week.
80% = iPhone ONE ready for distribution in USA and abroad within 90 days post MW
100% = iPhone ONE and TWO (smart-phone) ready for distribution in USA and abroad within 365 days post MW
My probability SWAG on modus operandi for iPhone service/support ...
50% = Apple will use a Mobile Virtual Network Operator (MVNO) strategy to launch iPhone. A MVNO would lease carrier lines and provide service/support directly to users (hence more Apple control over users' experience). One important qualifier - Apple MVNO may
not be ready for first gen (iPhone ONE) launch. IMO it's more likely that Apple MVNO will be ready for iPhone TWO - ETA is 3rd or 4th quarter of 2007 or early 2008.
30% = Apple has agreements in place with carriers to support the iPhone (e.g. Cingular in the USA and T-Mobile in Europe, etc.). Could also be multiple carriers here and abroad.
10% = Apple launches iPhone as a "free agent" (unlocked and ready for any carrier).
10% =
Surprise! There is NO cellular. It's just a VoIP ready iPod using Jahjah or Skype type app with iChat.