Where did you get your version of MyWi to get it to run on your ipad 3g? The one I used made my ipad turn into a messed up iphone with a tiny keyboard. I had to uninstall it to make it normal again!
I installed 3.5.2 and I get full bars on the wifi signal strength, Problem is you wifi devices needs to be able to see ad hoc wifi networks. I read Ipod/Iphone can see ad hoc, laptops, computers can too. Android can't at the moment.
I just installed MyWi on my 3G iPad and was able to then connect my laptop to to the iPad and use it's 3G service to access the internet. Worked great.
This means that you should be able to connect anything, like a Blackberry or desktop/laptop.
I have a dumb question (I am a newbie): hypothetically speaking, if you could tether a laptop to a 3G iPad with an unlimited plan (making your iPad 3G act a hotspot), how do you make your iPad 3G a secure network (you know, secure vs. unsecured) ?