Microsoft (NSDQ: MSFT) announced yesterday that it would allow ads on two of its mobile services—Windows Live Messenger and its Windows Live Hotmail. The ads—in the form of banners—will be available in France, Spain the UK and US. The company also said they were planning to offer mobile search advertisements on its Live Search Mobile service later this year. The program is similar to what Google (NSDQ: GOOG) rolled out in April, in which advertisers create keyword campaigns through its AdWords program to display banner ads on its mobile search service. Yahoo (NSDQ: YHOO), too, already offers an AdWords-style service as well as banner ads on its mobile services (release).