Seems that Bob is not the type of person that represents reliable sources..........or rather is authorityless

Noxious Bob, please cite your sources...

Completely agree, the business logic wouldn't support an announcement this early. If it was announced at MacWorld it would need to go on sale within a month to prevent sales taking a dive (Apple's profits come from hardware sales not iTunes, etc). With sluggish sales Europe arguably needs the 3G iPhone most but releasing it two or three months after the original would p**s off European customers.
The 3G iPhone will probably come out in June, one year after the original but it will be announced in May and the release will probably be worldwide (no release of the iPhone yet in Asia remember). Both Europe and Asia would get a boost from a 3G iPhone so a US first release wouldn't make sense.
As for MacWorld announcement, the new firmware 1.1.3 doesn't sound enough but the rumours of this seem pretty conclusive that it will come and what it will contain. 
I would have expected a bigger, 1.2.1 release uncrippling bluetooth and providing landscape keyboards outside of Safari, voice dialing, disk support and a few of the other things on the iPhone user wishlist (remember Apple saying it could sort out a lot of the complaints with software updates?). 
It is likely, therefore, that there could be an announcement of a 16GB EGDE iPhone to tide things over until May and the announcement of the 3G version. Not to mention one or two more firmware updates along the way...

I have it on good authority that come March when Apple launches the iPhone in Canada it will be a 3g model.