Here is how you cure asthma

I have permanently fixed my asthma (exercise induced)..

Asthmatics generally hyperventilate or over-breathe up to 3 times more than a normal person would, unknowingly, even between attacks.
During attacks, their breathing increases even more. This encourages spasm of the bronchi and decreases the efficiency with which oxygen is taken up.
Asthma is the bodies self defense mechanism to protect itself from over breathing. It constricts the airways to try and counter overbreathing.. When we overbreathe the carbon dioxide levels in our blood drop too low and when they get too low our bodies self defense mechanism kicks in. 

Check out:
http://members.westnet.com.au/pkolb/buteyko.htm
http://www.buteyko.com/
and google buteyko.

Practise underbeathing, just sitting here on the computer, so you feel a slight need for more oxygen.  eventually you will adjust.  Also expel most of your air and hold your breathe, see how long you can hold it for.  practise this.  Severe asthmatics, after they have expelled all the air from there lungs cant even hold there breathe for 5 seconds.

It makes perfect sense aswell.. Some people find that swimming fixes their asthma. Why ? Well when people swim they take 1 breathe every 4-6 strokes.. significantly reduced breathing, which raises co2 levels in blood. In Europe they send people to the Alps for a month for the sole reason of fixing asthma and people in Aus that go to the snow for a week often find it fixes their asthma. At high altitudes the air is alot thinner.  I know its against medical information, who conveniently make billions off lifelong asthmatics and choose to manage rather than cure.

"How Effective Are The Exercises ?
In November 1994, medical trials, sponsored by the Australian Association of Asthma Foundations, were started at the Mater Hospital, Brisbane Australia. Six weeks into the trial, the group practicing the Buteyko breathing exercises, had reduced their bronchodilator (reliever) medication by 90%. Six weeks later they had also reduced their steroid intake by 49%. The control group practicing physiotherapy exercises were using the same amount of steroids and 6% less bronchodilator (reliever) medication after 12 weeks. See more Buteyko Method case studies.'

I know how much of a setback asthma is and how severly it can limit the fun factor in life.. for me it limited performance in sport.

On a personal note.. I picked up asthma because when I used to run, I started to focus heavily on breathing, instead of breathing naturally, thinking the more I breathe the more oxygen I get, the less tired I'd get.  The overbreathing caused my CO2 levels to drop and in turn my body fights this and the asthma symptoms kick in.

Also.. Use your whole diaphram to breath.. such that your stomach rises and falls when you breathe.
Hope it helps !!