Application for geo-mapping my photos iPhone

Googles own Picasa software can geo-tag pre-existing, non-tagged photos.
http://picasa.google.com/
iMac 20", MacBook, Time Capsule, Airport Express, AppleTV 2 Mac OS X (10.6.6) iPhone 3GS 32GB, iPad WiFi 32GB

I presume my questions has been misunderstood.
I am looking for an application in iPhone. I want to use this geo-tagging ability in a photo application for my iPhone.
Moreover, I cannot install any software to my laptop since its a company laptop. I dont have any admin rights
iPhone 4 iOS 4

No, your question was not misunderstood. You said:
I have many photos that I took before the time of my new iPhone 4
so these photos must exist somewhere else - the most logical place being on your computer.
When photos are synced to an iPhone 4 they are reduced in quality and size, as they are optimised for the iPhones screen. Surely you would want to geo-tag the high quality originals, not the reduced quality copies?
I cannot install any software to my laptop since its a company laptop.
You didnt mention this fact. You just asked for any application (that works online/offline, free/paid) and/or ideas.
Have you searched the AppStore for geo tag?
iMac 20", MacBook, Time Capsule, Airport Express, AppleTV 2 Mac OS X (10.6.6) iPhone 3GS 32GB, iPad WiFi 32GB