I don't know if you are going with Virgin, do not use their pre-booking service for these tickets. We 'booked' last July for 6pm show on 18th Feb, we thought! Having paid in full we collected our holiday tickets and found that we only had a voucher, when I rang I was told that it was subject to what was available at our Welcome Meeting (which we hadn't intended to go to anyway). As first Meeting was 15th and we wanted 18th I was not happy. Rang Virgin Rep in Florida (haven't had phone bill yet) she said lots of people come with voucher and at busy times end up going home never having seen show and have to ask for refund. It's President's week when we go so it seems that we would be disappointed. Could book on the net but Virgin want £100 cancellation charge for tickets they never even purchased. Numerous calls, e-mails, letters later they have agreed not to charge and we booked on the Cirque website.
Really disappointed by Virgin's handling of this, thought we had booked tickets and nothing in brochure indicates otherwise, so be warned, if you really want to do this then book confirmed seats only!
We're booking for April now too, whilst the exchange rate is so good. 
