Question: I have a project to designing a website to search Zip codes on a digital map.
Somebody advised me to use PHP with postgreSQL or MySQL.

My professor wants me to tell him why I chose this for a mapping site.

The question is... Is there an expertise web language for GIS site ??
What is the difference if I use MySQL or MSsql or even Access if there is a connection to other remote database ??

Thanks

Answer: 
Use language and db you are most comfortable with + Google Maps or Microsoft MapControl. 

If you are asked why you chose these technologies, you can tell the truth - you are most comfortable working with them, that way you are most productive, because any language or db is fine.
PHP and MySQL are highly available, usually free, have a less-steep learning curve than most and offer (like many languages) exactly what you need.

I've done several mapping projects using google maps, location searches (based on LAT/LON or ZIP codes), interactive mappings and KML data. MySQL and PHP are more than capable.