Can someone help me with the pronunciation?

Hey everyone!

i must say, i love ChinesePod. In just one week i learned more than a month in other courses. But, i really have trouble with the pronunciation, like the word "cai" (i'm sorry, i don't have a way in my computer to write hanzi, well, not yet) for "food". I tried to say it, i swear, but i never got it right. So, there anybody who maybe could like me with the tones?, maybe with microphone? I'm serious in learning Mandarin, so maybe we could keep writing. Someone? i'll really appreciate it.

 Daniel