Doesn't Everybody Do This Already?
...or maybe it's just me.
Talktoaliens.com offers to transmit your message Out There. From their FAQ:
Q. Where in space are you sending my messages?
A. Based on discussions with astronomy consultants, we decided to point our antenna into the area of the sky with the highest density of regional stars (and, thus, hopefully planets and other civilizations). That region is commonly referred to as the "Milky Way" -- the galaxy in which our own solar system resides. As the sky appears to turn over the earth, our fixed-mounted parabolic antenna sweeps through much of the Milky Way Galaxy (and its estimated 400 billion stars). For more information on the Milky Way Galaxy, visit: http://www.seds.org/messier/more/mw.html
Q. Why do you charge $3.99 per minute? And why is it through a 900 number?
A. This entire service is funded and run by a handful of individuals who have put in considerable personal money and countless hours of time. The fee will help us begin to offset our equipment and time investments, and help us develop new features for our service. The 900 number keeps things very simple. You only pay for the time you use. It also eliminates the billing complexity and fraud commonly associated with credit cards.
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Q. Can I say anything I'd like in my broadcast message?
A. We strongly encourage that you refrain from any profane or indecent language. As mentioned above, it is highly unlikely that anyone here on earth will hear your messages. Even so, it would seem prudent and polite to keep your language respectable. Feel free to speak your mind, sing, chant, rant, etc. to your heart's content. Be a good "Earth Ambassador" to any civilizations that might be tuned in!