One of Apple's bigger oversights/neglects with the iPhone has been providing a way to synchronize the iPhone's notes feature with a PC/Mac. It's just outright dopey that they have yet to address this.
As for transferring files and documents to your iPhone, you can if you've jailbroken it and installed some 3rd party apps to enable file transfers, read documents, etc. If you KNOW what you are doing and can follow directions very well, there are tutorials online to help you do all this. There's always the risk that you could brick your phone, though in actuality I don't believe anyone actually has done so (only bricked ones being those that were hacked to unlock for use with other carriers... a different process).
I'll point you to those tutorials if you like.... and if you are SURE you want to do so. Otherwise, I recommend waiting until Apple has released an official SDK for the iPhone (due in March?) so you can more easily and safely add apps.
One other alternative is to email yourself documents in PDF format and read them in the iPhone's email client. That works out well... not sure what other document formats are supported, I'm sure plain text documents are, and possibly Word documents are as well. Just email one to yourself and try it.