Only the HD-capable boxes (V-HD, V+ and TiVo) have an HDMI socket. You can get an upgrade for V-HD for £20.
http://shop.virginmedia.com/existing...de-to-vhd.html
Or if you'd prefer a TiVo, details are here
http://shop.virginmedia.com/existing...ox-prices.html
ps. Welcome to the forum!