thats twice today my post went before it was finished. to continue- there are blokes in hi-vis jackets to show you where to park, but back to the route.
The NEC isnt in birmingham itself but right next to the motorway junction for Birmingham Airport.
All you do is get on the M50 at your end, carry right on up and join the M5 Northbound. past Junction 6 north the Motorway splits and you stay in the Left hand lane and follow M42 airport. Just keep following the airport signs,they will say Airport NEC. Watch your speed down the M42 though, they have the speed limit lit up all the way along and whatever it is on the day, say 50mph; make sure that you stick to it or you'll get done. I've forgotten what the junction number is,somebody on here will know it or i'll find out and post it, but you can't go wrong. The traffic isnt usually that bad, and you dont have to go near any town centres or anything, its all motorway.
When you come off at the motorway junction its the second exit and you're there.
Hope this helps.