How can I create interactive a map on my website that shows my coverage area

I am trying to creat an interactive canadian map that shows the business territory (coverage area) on my website. When users will go to my website and enter address or postal code, the map should return the service area higlighted. (For exaple if you go to any cell phone websites and the map shows the coverage area)How can I do that?
Do I need hosted web service? How much does it cost?
Sorry I am newbee and please answer in simple words. I would appreciate your help a lot.

Hi,

I think you need Microsoft Virtual earth or Microsoft Web Service. I did not experiment already with these products but I think this shoud easy be done. There is another forum for both of these.

Arai,

I would recommend the Virtual Earth service as you can try it out for free without signing up for any trial account or needing credentials, also it is a lot more cool :-)

Eric