definately checkout that similar thread.
this numbness is a constant battle for me.
some of which stems from neck and shoulders being in their position for so long - this was the first place the doc at SportsMed went when i mentioned it to him. so flexing the shoulders and neck periodically has definately helped.
the tightness of your gloves is also a factor - loosening the velcro also helped. as does varying the padding as well as it's position on the gloves.
lastly, constant movement around your bars will also help - on the hoods, back from the hoods, on the flats, on the drops, as well as varying where the main contact of where my hands are on the bars too. ie; hanging your hands off the side of the hoods with the main contact being via the thumb, as opposed to taking most of the pressure on the large pad on the inside of your palm. alternatively when on the flats, whether you rest on the base of your palms or the tops of your palms (under your knuckles).
all of the above has helped me do several hours of riding with only nomial numbness, compared to having it start within 10mins and losing the ability to use my hands properly after an hour...
one last point - make sure your fit is right too. mine was wrong and had too much weight forward on my hands. i've now got both a new headstem and narrower bars, which have made quite a difference too.
good luck!!