I want to get started with mobile development, but am not sure where to start.
Which should I choose to start with, iPhone, Android, Blackberry, or Palm?
iPhone seems to be pretty easy...
Any advice or resources for someone just learning about mobile programming?
Edit: I mean developing apps for the phone hardware.
Well, pick a device and start from there, because they are all different. I take it you are talking about local applications, and not just websites optimised for them?
Once you pick a device you can easily find a tutorial from there.
It's all about you and your preferences. If you want to focus yourself on business users (calendars, office applications), choose Blackberry. If you want to program, well, how do I say this avoiding flame-bait..., some "casual" applications, iphone seems to be a valid choice.
On the other side, Blackberry and Palm are platforms that are going to be forgotten in some time. I don't know is it smart option to START programming now on these platforms. Android and iPhone are "next generation" smart phones, in my opinion.
If I start now to program for smartphones, I took Android.
Well, depending on you invidual case, this might not be just a duplicate of
http://stackoverflow.com/questions/1092144/what-mobile-platform-should-i-start-learning
One possible way to look at this is: What language do you already know how to program in?
If you already know the basics, then you mostly need to adapt what you know to a resource constrained device with a small screen, avoid battery drain and deal with mobile wireless connection issues.
Palm Pre development is only targetted at its web browser.
iPhone is Objective-C.
Android, the standard part of it, is Java only but it has its own APIs.
Blackberry is J2ME only, with proprietary extensions.
Windows Mobile is J2ME or the .Net compact framework.
Symbian lets you choose: you can target one of the web browsers, use Symbian OS C++, use more standard C/C++, python for Series60, NS-Basic, .Net, J2ME, Ruby or write your own runtime!
For resources, start with each manufacturer's website before asking more targetted questions here.