Why is my MacBook Pro constantly losing the wifi connection with my WRT150N router?
If you are certain that your Wi-Fi connection works fine when you are somewhere else, there might be signal or compatibility problems between your router and your Macbook Pro. Contrary to popular belief, wi-fi connections are not a voodoo thing, and they just involve radio waves, just like a cellphone and any other wireless device. 

Reasons for a Wi-Fi connection being lost could be quite a lot, but usually interference and signal noise are the two primary factors. Where some devices are able to “maintain” the connection (despite the possible errors), others simply fail and drop it more often. 

Wi-Fi is designed to continue working despite “small interruptions” (albeit with a decrease in performance due to ‘retries’), but sometimes this is not possible and connections get dropped. 

Sometimes the problem relies in the encryption. When the network is not open and it’s traffic is encrypted, this “overhead” causes more drops than the usual.

Possible solutions are resetting the router to factory settings and reconfiguring it, changing the channel from Auto to something allowed in your country, making sure your Operating system / Computer has the latest drivers/patches/etc. and there isn’t really much else you can do.

You can try moving your router to another physical position.

I’ve read a few posts about that specific router model and Macbooks having problems, so also assume there might be a problem with that model (or some revision of the router) and OS X.

You can always try to see if the Console has some relevant error messages (/Applications/Utilities/Console.app).