How long does it take to mine my first Bitcoins?

[640]

I've signed up for a Bitcoin account, signed up for a wallet, found a mine and started mining with an app I purchased with my LG Optimus G. Every few seconds it tells me I've, I guess, mined 640 khashes (as in kilobytes, but kilohashes?). The app says it may take a while for the work to be registered by the operator.

So, how long does it take to produce bitcoins in this manner? Is there a rule of thumb for how long it takes different hardware to produduce bitcoins? Am I even thinking of producing bitcoins in the right way? Reading about the method of bitcoins makes me feel like an idiot...