1) Obviously because you wouldn't want to get your raspberry pi wet, is it possible to transport data wirelessly? I was thinking I could update data to a website but well... That will just cost more and use up more of my time! Is there any sort of thing I can use to connect two gpio boards? for exam...

The rain gauge (or any other sensor) will output its data through an interface its designers thought most useful. If you know - or can find out - what that interface that is, you can program the Pi to accept that and use the data. You may find that it uses one of the more common interfaces - I2C, S...

When programming with Raspberry Pi say you're using a sensor, uh, for example, a rain gauge! If you got that rain gauge off of a random website would you still be able to use it with the Raspberry Pi? Also, like some sensors have their own modules what about if it doesn't have it's own? How does it ...