You should add as much weigth as possible to make flpping harder. This will also give the robot more momentum. Also, a wider robot which is low to the ground is extrememly hard to overturn.

There is an app called LegoDrive which can control an nxt bot via bluetooth.
This app is on the Cydia marketplace and is available on "Jailbroken" apple products only. *Jailbreaking can do permanent damage to the Iphone or Ipod*

U can unjailbreak but you have to restore it. I recomend using it if you've "already" jailbroken your iphone or ipod.
you could always back up your files before restoring. To me jailbreaking does more good than harm

some programs on it can be harmful. I had to restore my ipod three times

i agree. the lower center of gravity makes it harder to flip over

^ then it will be easier to flip the front

I also think it is a great idea but when you are getting pushed over the edge, cliff detection most likely can't stop it

it would be best if we placed the senor along the left edge of the black line

i have no idea