Ok, Here's a few things that I have found on a website(please don't ask for the site cause i dunt' remember it and forgot to save it). I've got spoilers/hints from JK for the last 2 books...here's some for the 6th book...
-Lucius Malfoy will be killed by Voldemort or an Auror
-Sirius Black, The Dementors, Dobby, Crookshanks, and Aragog will all return.
- Harry will find his true love...and it isn't Cho.
-The Chamber of Secrets will make another appearance
-There will be another werewolf at Hogwarts.
-Prof. Sprout will retire.
-Harry will fall in love with a Slytherin girl. [spoiler] Doubt that this is likely to happen, but here goes: Harry starts dating PANSY PARKINSON, which makes Draco mad so Draco decides to pretend to like Hermione to spite Harry. Hermione and Draco start 'dating' and Ron gets REALLY jealous and realizes he fancies Hermione. But then Draco finds he really likes Hermione! they are snogging one night when Krum steps out of shadow! He had come to see Hermione! He gets mad and kills Malfoy cuz hes a DEATH EATER secretly. So Ron and Hermione start dating. Harry finished with Pansy and realizes he likes Hermione. He tells Ron and they fall out. Hermione doesn't know what to do!
-It will be shorter than OotP...probably the same length as GoF.
That's only a few(very few) of what i have found and that's all i'm going to tell so that i won't spoil much.
here r some rumors i found:
Our old friend the time-turner is used to bring
back a certain "dead" godfather...
Hermione will be hurt bad, then Harry and Ron will fight together against Voldemort
Hagrid goes back to school.
JKR said in the interivew on the DVD for Chamber that there was something small in Chamber that was going to be very big in book six.
(what van it b!?
We will see more of Nocturn Alley in this next book, different areas and who shops there
Snape's past will be revealed. Why he left Voldemort will be revealed as well
JKR did say in an interview that Lily and James were both Gryffindors
and well i notice tis by myself dumbledor=mud bleedor
http://www.hpana.com/news.18156.html
Here, when someone asked how long it would be until the 6th book comes out, she replied "Oh, not too long, but I don't like to say." Talk about leave you hanging even more... 🙁