I always have thougt of that bacause it always happens to me. I am a engineering student and I work as a spanish teacher, and i have many things to do and dont have time to practice English and when I am in free time I tried to read or listen english music but I think that is not suffient. If you were me What will you do?
If I were you I would follow Steve’s blog, read his book
“How to learn languages in the age of the Internet”.http://bit.ly/bXdJnB
One can always find time.
Instead of music try to listen to podcasts.
Install iTunes, create American account, and enjoy.
I recommend eslpod and of course linguist podcasts.
Most of my learning activity, perhaps 80%, consists of listening to my MP3 player while doing other tasks.
Do stuff you would normally do in your native language, in your target language. Eg read novels for relaxation, listen to the news on the radio, watch films on TV, and write your diary and shopping lists, all in your target language.
It’s what I do and it drives my family mad 
Skyblueteapot, those are good ideas, especially about the diary. I rarely keep a diary, but I must say when I lived in Italy for a short while, I wrote a little trivial diary in Italian. I’ve still got it, it’s funny 
My own idea: translate the lyrics of pop songs or indeed any songs into your target language. This is usually quite easy, and it alerts you to not knowing some basic words. If it’s too easy translating literally, try to translate it so that it still “scans”, i.e. the song can still be sung to the same tune. This can be done in the shower, or on a boring bus ride where you would otherwise just be languishing.
I was once listening to Russian radio, and they played the Dzingiz Kahn song where it goes “Moskau! Kalt und geheimnisvoll…” Then the two DJs went through it line by line translating it into Russian. It was funny.