All those who expressed an interest in early March (or later) should have received several email updates from RS Online, entitled "Raspberry Pi Update" by now.
I have received 6 in total the first one being dated 15th March and the last one I received was on 8th May 2012, but they could of course end up in your 'Spam' folder. Despite the promise of "More news next week" I haven't heard any more from them since then.
If you haven't received any of these at all, then it is unlikely that you are even on their list, and I suggest that you either contact them directly, or register a further 'Expression of Interest".
For those of us who are still waiting, let's hope we hear some good news soon!