Creating Landing Pages For Major Cities In The World?

[AK]

I have a website that offers a small online service. This service is useful all over the world. Is it ok from a search engine point of view that I create landing pages for major cities in the world so that if someone submits a search query for this service specific to his/her city then my website shows up?

The format of the landing page is such that it contains description and useful tips about the service, but with such keywords that it shows up against queries like "[service] in rome itally".
@ Julia,
I mean that all the landing pages are with the same content (descriptions and tips about the service) but with different keywords embedded here and there so that each page shows up for searches in different cities of the world.