ATC83 There will be no large-scale recruiting for the forseeable future. With no new aircraft or routes planeed until 2011, and the airline pretty much up to establishment, there is no need for new people other than as attrition replacements. As pilots tend not to leave Virgin until they have to, and retirement has (as for every UK airline) gone back 5 years, don't expect much movement there.
As for minimum qualifications, yes, the airline will look at you with 2500 hours as that is the stated minimum. However, the vast majority of applicants have a good deal more than that, and therefore rather more than 2500 is the norm at entry. While it's not impossible to be accepted with the minimum hours, the competition (and my experience) suggests that it's very unusual, so don't get your hopes up. As Stan says, this airline is heavily oversubscribed by experienced pilots and has the luxury of being able to be very choosy about who it employs. That said, I got in (with 7000 or so hours, and 15 years' command experience)!
Command will be a long time for any new joiners now. Recent commands have been after 8 to 9 years in the RHS; the hiatus in expansion couples with the raised retirement age means that this will inevitably move towards 12 years or more. This is hardly surprising; as the airline matures and its expansion rate slows, its longhaul-only ethos will naturally mean a long time to command. Fortunately, the pay scales for senior FOs are pretty good!