Use Google Music. Relatively complete.

You can also search Lyric on Google, which is an American lyrics website with a good reputation. I have found many super unpopular old songs on it.

There is also myspace, which has the homepages of many foreign bands and musicians.

If you still can’t find the song you are looking for, you can ask me. I can help you ask foreigners on Yahoo’s US or UK ask (similar to China’s Baidu)~

Hope it helps you^_^