The beta is available in a variety of distributions for the various multi-touch products Apple has released over the past two years, each of which weighs in around 250MB. The updated version of the iPhone SDK is much heftier, at around 2.5GB.
Generally speaking, developers are excited about the release and say the beta is stable enough for them to use as their primary iPhone OS for the time being, though the software is clearly 'not something Apple would ship' at this point.
In particular, Spotlight is said to be very responsive and functions just as you would expect having used the feature previously on a Mac. Copy & paste is also well received, but feels somewhat flaky. Developers have experienced some difficulty making selections in Safari, which may suggest a slight learning curve like that required when exploring the iPhone's touch keyboard for the first time.
Below are a series of screenshots highlighting some of the widely publicized features of iPhone 3.0 and some that have gone unmentioned, like encrypted iPhone backups, background messaging and Camera app tweaks. Two apps that have reportedly seen no changes as of yet are Weather and Clock.
Copy and paste
Copy and paste works across all applications. We've detailed the process for text, web content, and photos in a series of annotated screenshots here. Below are some additional examples, including copy and paste of MMS messages. There's also an interface in Safari for copying URLs.
One cool feature of Apple's new MMS "Messages" app is the ability to send messages in the background, which lets you type out your second message while you're waiting for the first to send. It's quite helpful when sending very large media messages:
Voice Memo interface
Apple's new Voice Memo application lets you record voice memos for yourself, which can then be trimmed and sent to friends, family, or coworkers via email of MMS.
Spotlight and Mail search
Spotlight search is accessible by flicking the iPhone's home screen to the right (as if there was a home screen to the left). In addition to serving as a global search app, it can also act as a quick application launcher.
Mail, Notes, iPod and Calendar also have their own integrated search interface (seen in the shots below, which are flanking the new home screen). If the mail search doesn't turn up any results from messages stored on your iPhone, it will move on to search messages still located on your mail server.
Key apps getting landscape mode
Among the apps gaining true landscape mode with a landscape keyboard are Mail, Stocks, Notes, and Messages:
Camera and Photos
A new version of Apple's Camera app shows you the last photo you snapped in the lower left-hand corner of the application. Meanwhile, the new Photo album app allows you to copy, delete, or share multiple photos via email.
YouTube and Settings panel
A new version of the YouTube app due in iPhone 3.0 will let you log into your account and see subscriptions, playlists, and history. Below is also a photo of the iPhone's general preference pane thrown in for good measure. There are reportedly few changes in the settings.
Parental controls & contact sharing
Below are some of the new parental controls and the dialog that allows sharing of contact cards (vCard standard) over MMS.
New screenshot interface
The version of the App Store application included with the iPhone 3.0 beta includes a slightly revised and quirky interface for viewing screenshots:
Encrypt iPhone backups and Note syncing
Below are two screenshots from the current version of iTunes showing options to encrypt iPhone backups and sync notes to handsets running iPhone OS 3.0.
YouTube user Jon has posted the following nine-minute walkthrough video of iPhone OS 3.0: