Hi Rigout and congrats on your iPad2 gift. I bought my wife one earlier in the year and it has probably succeeded in wasting a good 500 hours of her time by now...
iPad uses Safari browser and that browser can be used to access InfoPath forms that reside in a SharePoint library or list. SharePoint has a special service called the InfoPath Forms Service which will display the forms in the browser. We have many consulting customers that use iPads to fill out forms. To design the forms, you'll need InfoPath Designer and you'll need windows for that, but for filling out forms, you should be able to do it from an iPad.