I'm a native English speaker, so I didn't have to learn English, but I did learn Spanish, and I think I agree with Andrew; you start to think in a different language the more you operate in it, the more you are immersed in it. It's really cool when the switch takes place, when the "translation" in your head doesn't happen anymore. It's cool when you are remembering a conversation and can't remember what language it took place in. It's cool when you dream in the other language too :) Definitely something to look forward to! I'm sure it'll happen for you!

I'm italian, I learned the english language 15 years ago and I remember that, when I was reading a lot of books (novels, poetry ect) I came to the point of being able, during the day, to think something in English, in a natural way. The "secret" is just this: once you have the basic of a language, read, read and read! read novels, read on the internet, read newspapers, read the instructions of a cell phone, the more you read, the more you'll be able to fell the second language as your own.