How to disguise ciphertext
What you are looking for is called steganography. It is a different field from cryptography so you might want to check in some other fora also.

I don't know much about steganography but i remember this paricular algorithm. You can take you ciphertext, and an image say a greyscale bitmap. Then you can replace the least significant bits of every pixel with a bit from your ciphertext. Since ciphertext are "random" bitstrings one would no be able to recognise a ciphertext from random noise on the pixel values.

You can then reconstruct the ciphertext by reading the last bit from each pixel.