Apple's Worldwide Developer conference for 2014 starts today at 10AM PDT (6PM BST). It's where Apple showcases its new software and technology for developers who are involved with Apple products such as iOS and OS X.
We are expected to see the new iOS 8 be announced which shouldn't be as drastic in changes compared to iOS 6 to iOS 7 but we should see some very nice updates to the software and capability. Apple will also likely announce new apps for iOS 8.
The new version os OS X is also expected to be announced. Rumours are flying around that OS X 10.10 will be called Yosemite and may have a drastic redesign like iOS 7 did last year.
We may even hear of some new hardware such as updated Macbooks or iMacs but we probably won't hear of a new iPhone or iPad.
Apple is live streaming the whole event via its site so they definitely have some important announcements to make. They may also live stream the event on YouTube but that hasn't been confirmed yet.