The "ch" can have 2 sounds in german, both are a bit similiar though, and they both dont exist in the english language.
But at least one of them exist in other languages, such as spanish for example.
One version of the german "ch" sounds exaclty like the Spanish "J" in Jorge, or "J"uan or eno"j"ado for example. This version is used for example in words like : Bach, wach, noch, doch, gemacht and others.
Here you can listen to this sound : http://www.myjmk.com/voice.php?tsearch=enojado&tlang=1
http://forvo.com/word/bach/
The other one is hard to find, I think I haven't heard it in another language so far, it's kind of the same as the other ch, but it is spoken differently. Whereas the other "ch" is built in the back of your mouth or better said throat, this one is built more in the mouth than in the throat.
It is used in words like : Ich ( i noticed, that most foreigners have a hard time making this sound, some ppl say something like "isch" or the ich with the other ch I mentioned before.) weich, erreicht, teich etc...
Edit : Here's an example for the this "ch" too : http://forvo.com/word/reich/
The crazy thing is, that you can absolutely not know which "ch" is used in a certain word, it just has to be remembered.
Well, I hope I have helped, german is a very hard language and things often are not logical, but I hope I could answer your question.