I'm surprised, that you are glad to hear, that a country with relatively unstable government is making progress toward having ballistic missile capabilities. Actually scratch that. It is progress toward ICBMs, not just ballistic missiles.
Well, one fact to keep in mind - developing capabilities to launch satellites [payload to orbit] is inseparable from capability to launch ICBMs. That's why first sputnik was both, so inspiring and so scary.
As to 'never allowing this to happen'. There are no such guaranties. I'd guess, the opposite is true. Technology [and as a result advanced weaponry] is only getting more and more accessible.
Here's a reference to the current state of the program: http://iranprimer.usip.org/resource/irans-ballistic-missile-...
And a bit more recent update: http://www.iranwatch.org/wmd/wmd-iranmissileessay.htm