Taken from the Vodafone website (since you can't link to the pages directly - bloody morons):
Vodafone Valentines Service
This service will send a Valentine's Day message to any mobile number - so that your loved one (the recipient) doesn't know who their secret admirer is!
To send a secret message:
Send a text message of the mobile number of your Valentine to 8666. This will deliver the standard text message of "Happy Valentine's Day from your secret admirer! Your Valentine by Vodafone"to your chosen mobile number on 14th February 2002.
Alternatively send the mobile number plus a message letter (from the list below, with a space in between to 8666. (E.g. 07777123456 C). This will order the requested message to be sent to the chosen mobile number on 14th February.
A. B my Valentine, Luv? . From Vodafone Valentines Service.
B. If I told you, you had a sexy body - would you hold it against me? Happy Valentine's Day....From Vodafone Valentines Service.
C. Hi, I'm Mr/Miss Right. Someone said you were looking for me! Happy Valentine's Day...From Vodafone Valentines Service.
D. As it's Valentines Day, can I ask, will U marry me?...From Vodafone Valentines Service.
E. I just wanted 2 say that I luv U ...From Vodafone Valentines Service.
You will then receive a confirmation message from Vodafone. To send an anonymous message costs 35p inc. VAT.
Non-Vodafone customers can also use the service by calling 09003 300300. These messages will be sent on 14th February in the same way. Calls charged at premium rate (50p per minute from a BT fixed line. Call charges from a mobile may vary).
Messages will be sent to Valentines from 7am onwards on 14th February. Messages will be accepted up to 12pm on 14th February Although messages will be sent out on 14th February, we cannot guarantee that they will be delivered on this date if the intended recipient has their phone switched off etc, but will continue trying to deliver the messages for 72 hours.
In case you were wondering, my mobile number is on the contact page ;)