Newbie questions about updates

[Stegozor]

Hi,

I switched to Ubuntu around 10 days ago and I have some newbie 
questions. Here's some of them related to updates:

The latest Firefox version available for GNU/Linux are 1.5.0.6 but 
Synaptic suggests 1.5.0.5. As for OpenOffice.org, the latest version is 
2.0.3 where Synaptic has 2.0.2, and for VLC 0.8.5 and we have  Why 
doesn't Synaptic have the latest versions? Is it a delay due to the 
"debianization" of the packages, or is it something else? How much does 
it take to make a debian package for a software (just a general idea) ?

I've also heard that canonical provides only security updates. Does that 
mean that to get newer versions one has to manage that himself? If what 
I heard is true, why doesn't Canonical update its repositories with 
other software than security updates? I'm just trying to understand.

One last thing: when the new version of Ubuntu is available, will it be 
easy to switch to it?

TIA.