We have some information coming out of Poland on what is in the November's White Dwarf, regarding Necrons. Some new units and new models are listed, here is the information.

Please remember that until we see it, these are still classified as rumors.

via Herr Dexter
A polish portal Cytadela.pl posted very interesting news today, lemme translate the Necron related part that for ya:
Some time ago I mentioned that new Necrons will appear in October's White Dwarf - I just got a confirmation of that info from a reliable source!

In the upcoming WD you will see some new units:
- Triarch Pretorians/Lychguard - think Ushabti with Grey Knight-like spears / glavies

- new Immortals

- new Destroyers

- Deathmarks - Necron snipers

- new HQ'a / characters - Overlord and Cryptec, those will be in finecast

- Command Barge - with a Lord on the throne

for those readers in Poland, here is the link.
http://www.cytadela.pl/modules.php?name=News&file=article&sid=1766