So far the big news out of the 2009 Apple Worldwide Developer Conference is all about the iPhone 3.0 software upgrade. A variety of new and cool/useful firmware functionality should plug a bunch of holes in the usability of iPhones as well as provide new opportunities for the companies who create apps.

A lot of the upgrades they’ve announced are smallish, but for anyone who plays and (especially) works on their iPhone, they’ll be welcome additions. Some of the highlights announced so far:

• Push notification system for alerts – Apple decided to build an OS that doesn’t allow the running of background apps, due to concerns about battery life. But with push notification, apps that aren’t turned on can now send you an alert when something needs your attention.
• In-App purchases – This will allow for the monetization of all kinds of apps, which will allow companies to develop cool, expensive applications which they can monetize by encouraging user spending. There’s tons of potential here, though it bodes ill for the wallets of those of us users who are impulsive purchasers.
• Cut-and-Paste  – The inability to do this stuff on iPhones was one of the things people complained about loud and often.
• Spotlight Device Search – Just like on your home computer, you’ll now be able to do a search of your iPhone to locate pictures, emails, songs, contact names, whatever.
• Undo Gesture – Just shake your iPhone and it will undo the last thing you did.
• Bluetooth-based Connectivity Between Devices – Multi-player iPhone gaming anyone?

Those were just a few of the highlights so far. The conference just started a couple hours ago, so there’ll likely be some more new announcements throughout the day and week ahead.