Traditionally holiday and festive season greetings are a fantastic way to use mobile marketing. Likewise from a consumer perspective holiday greetings show the biggest spikes in the year for MMS use.
A recent article found on mobilemarketer.com included some great hints on smart mobile marketing intitatives for valentines day. These include mobile video, valentines day strategies and loyalty programs the article is a great read and may give you some inspiration for a valentines day sales initiative.
The mobile being a very personal medium, valentines day is a great example of when mobile can be leveraged well to increase sales.
See the entire article here: http://www.mobilemarketer.com/cms/news/advertising/8794.html