If it's wire beaded you should be able to get it into a fig 8, but if it's one of the more expensive 'foldable' tyres, then pull it out from opposing sides (3 0'clock and 9) till it goes flat, and then roll it up. It's how you see them packaged and displayed in shops.
Folding a steel beaded tyre in two (from a figure of 8) has the potential to severely damage the bead by putting a twist innit. Far better to fold the tyre into three, like an 8 with another loop. Grab hold of oposite points on the tyre, bring them together until they cross, swap hands and tuck the two outer loops into the center. Voila! Happy tyre!
Wrap it in some plastic sheeting - I think I used the bag from a new armchair we had, stick it well with tape and stick the address label/stamps on it - let's face it it isn't going to break if they drop it!