Hello all just found this thread and think I will join in for the fun and excitement 
So heres my story - had place for London 2011 did lots of training was going really well then on my 20 mile run 4 weeks before the big day I seriously injured my foot. Deferred my place as there was no way I could do the marathon. Went to GP eventually seen orthopedic surgeon and am currently at home with my leg in a cast after having surgery 4 weeks ago 
It turned out I had an extra bone in my foot and some other technical stuff that I wont bore you with, but apparently I had been born with it and my increase in running had aggrevated the foot.
So I have my place in 2012 and there is no way I am not doing it!! I am planning a walk run strategy as I know I could not run full 26.2 as I wont fit the training in. I will be out this cast early Jan will do some physio and hopefully first run will be mid to end of Jan.
As I write this I realise I am being extremely optimistic but am hoping that I have managed to retain some fitness and as my plan is to run/walk I think this is achieveable - fingers crossed
Keep up the training everyone and enjoy it I am jealous of you all!!!