If he's going for 4870's then i'd assume he's looking for an LGA775 board.
http://www.novatech.co.uk/novatech/s....html?ASU-P5QE
I'd recommend the P5Q-E. It's £10 more expensive than the lower model, but it has better mofset heatpipe cooling. In Crossfire, the cards will run 8x PCI-e 2.0 but with 2x 4870's that wont make a difference from x16 lanes. Theres no point in buying an X48 board unless you're running Quadfire.