not sure if this is of interest to anyone, or if it's just plain lame or whatever, but here goes...you can send anonymous emails, (attached to a greeting card), through yahoo greetings www.yahoo.america. . .etings.com.
all you have to do is pick out a free card, and then click on the personalize button. you will have the options to enter a recipient, and then it asks you to enter a sender. you can put in whatever email you like, it doesn't require you to login with your yahoo email account to send it. i have tried this myself, and it does work.