Not wanting to put a downer on it, but there's no indication of a DVD on Universals website - infact that suggests a CD release! - and the Competition prize could simply be the 2 disc edition we currently have.
Speculation at best I'm afraid.
To reiterate an earlier reply, there's no mention of a DVD - from the listing at the link it looks like it is a CD, released on the same day as the last batch of studio reissues.
i would imagine that this particular one is being issuied earlier than the 2012 releases of the other live albums because it is their most popular/well known gig amongst the general public, and will therefore be a pre Christmas purchase for many people. In addition, it may be on the schedule to tie in with the announcement of some Queen live activity in 2011??
Well... Since one of the competition prizes is a "deluxe dvd" of Wembley, and there is a new release of the concert, it's actually possible that there is some truth here afer all.
Of course knowing QP's definition of deluxe, we can expect this release to be the same old 2 cds with 40 minutes of previously released video as a bonus dvd (or vice versa).
They also mention "an exclusive 'Live at Wembley' Fan Flight Case" as a prize too. My guess is DVD+CD plus a poster of the horrible coloured picutre of Freddie on the re-release and maybe 4 postcards of each member individually. Yay, Wembley again...