As Justin Kestelyn posts, this is the first time in his tenure that a public call-for-papers has been issued for Oracle Openworld.
The deadline has recently been extended until April 26. So if you were thinking about writing an abstract but figured you were going to run out of time, you now have an extra week. Oracle employees aren't allowed to submit abstracts :( as we are given an allocation.
If you are from a consulting company you may want to consider doing a joint presentation with one of your clients as these are always appealing. Are you running on an 11g Database and can talk to the advantages of 11g, experiences upgrading, etc. - then include details in your abstract. Competition for sessions is always intense so your abstract needs to interest (sell) those doing the reviewing - Good luck!
For all of you submitting an APEX abstract please forward me your entry (with speakers). Last year I was very lucky to secure a few sessions outside of the normal channels. I have no idea whether I will have any opportunities this year - every year the rules change.