Most block ciphers will be pretty much the same in terms of programming complexity as they have the same internal structure known as a fiestel network and differ only in details in how the non_linear substitution works,stream ciphers can be ss simple as xoring bits with a pseudo random sequence,or they can be pretty complex variations on AES.
Trouble is there is a trade off between complexity,security,and speed of operation when encrypting in software.As we always say the first thing you need to deside is how secure you want it to be.then you can deside how to implement it.Blowfish is a basically secure open source cipher which can be block or stream.Moe info would be good.