Mrvmo - I’ve only done two Pac rim trips since getting my iPhone so my experience is somewhat limited.
1. Have any of you ditched the laptop completely on the road and are just using the IPhone? If so how's it compared to the laptop?
No, because iPhone is good for internet ‘emergencies’

but that’s about it. Well, maybe a little more but seriously a laptop wins hands down.
2. How easy is it to "jailbreak" the phone?
Easy is an understatement. Go to youtube.com and type iphone unlocking in the search engine and you'll get tons of videos showing you how to do it - takes anywhere between 3-5 minutes and my grandma could do it.
3. Can you still get the necessary updates if your phone is unlocked? If not can the "unlocking" easily be reversed?
My friend unlocked his phone and it worked pretty well. However one day he connected to the iTunes to download some music and he 'accidentally' downloaded the latest iphone update and his phone went blank. He has not been able to bring it back to life and AT&T won't help him (obviously). I've heard some updates work just fine but some will corrupt the files. He has not been able to reverse the “unlock” successfully.
4. Can you use Skype on the IPhone (Both voice and text)? Without unlocking the phone? If so, how well does it work?
Well, I’ve tried “
IM+ for Skype” and Fring. Text messaging worked well on both, I was able to call on Fring but lost the connection within seconds. I tried several times but kept losing the call. (good WiFi signal at Starbucks).
5. Is the internet just as easy to use as the laptop? IE Can you access your email, banking, airlinepilotcentral
?
Well, I can access pretty much all websites however sometimes they take for ever even with 3G. I use the iPhone for quick & easy online stuff but if you need lots of typing stick to your laptop. Unfortunately, you cannot use your iPhone as a modem (like my old Treo) and I really miss that feature (I only used it domestically).
Text messaging is a huge disappointment, can’t even attach pictures taken with the iPhone to a text message like I did on Treo (you know, check this out… etc) instead you’ll get a choice of emailing it or sending it to your MobileMe account. Also, with Treo I could see when someone ‘read’ my text message (a check mark would appear) – no such notification here. I’d say text messaging is my biggest disappointment when it comes to the iPhone.
Overall, I still like the phone and do not regret switching from Treo but it’s not “The One”

as some people seem think…
Hope this helps.