AES Text Encryptor Made Easy

If you are concerned about the privacy of a message you like to send, here is an easy way to encrypt it : https://encipher.it/.
Just drag the bookmarklet to the Bookmarks bar of your browser.
I take Gmail as an example : just type your message and hit the Encipher It button. A small window will popup :

Just type in a password and hit enter. The bookmarklet uses AES symmetric encryption and PBKDF2 key generation to keep your email safe. All encoding/decoding is done locally in your browser.
After receiving the email the reader uses the same bookmarklet to decrypt the message : just hit the Encipher It button and type in the same password :

If you don't or can't use the bookmarklet just go to the website : https://encipher.it/ and use the text box to encrypt and decrypt messages.

Make sure the password is sent safely to the recipient !