FileWard is a nice file encryption utility for the Mac. It allows you to encrypt any file on your Mac with different encryption algorithms, including Blowfish, CASTS, Triple DES, DES-X, AES 128, and AES 256. The trial version is fully functional but it won't let you choose the more secure algorithms.
FileWard's graphical user interface functions as a drop-zone. You drag and drop the files that you want to encrypt and a new window will be displayed. This window will show the file name, and will ask you to type and verify a password and to choose an encryption cipher. After the encryption is done, you will see a new file next to the one you dragged to the application. This is the encrypted file. When you double-click it, you will be prompted to type the password. If you type the password correctly, FileWard will unpack the file in the same directory. Keep in mind that the original file is not deleted by FileWard, so if you are protecting sensitive files, you may want to deal with the unencrypted files as well.
In my testing, FileWard worked very well. I was able to encrypt and decrypt files with ease. I liked the password generator, which aids you in creating strong passwords for your files.