Found a very handy tool for S60 cellphones with GPS receiver. It works great on Symbian 5th edition OS as well.
UTM data makes use of A-GPS feature of your S60 cellphone and pin-points your location in wide variety of coordinates format (you have an option to choose from a list of supported formats). The accuracy level can vary from 40 meters to about 200 meters. You will be charged for the GPRS usage. Check with your service provider on the charges. It costs me about INR 10 paise (about 1/5th of a US cent) to figure out my coordinates. It allows you to view sunrise and sunset time based on your coordinate data. I think this data will be of significant use if you plan to trek. Say, you intend to trek at a forest range in Assam and you have signal access in the nearest town. You can plan your day trek accordingly based on sunrise - sunset data. Remember, Assam is not Delhi (and the vice versa) and since a country like India is contented with just one time zone, sometimes sunrise and sunset timing assumptions can be misleading.
Your cellphone (w/A-GPS support) along with a mechanical compass will be quite handy as you can mark your trail (in case you plan to explore out of the marked trail).
BTW, Google maps application for S60 phones also works great. Though it was intended for Symbian 3rd edition OS, it installs (with a warning) and works great on 5th edition. Added to it, the street view of images is just fantastic! Google maps will be of significant use if you are visiting Tier-1 Cities in India. I already did a short sampling at Chennai and it works great! Can’t ask for more for a free service!
You will be surprised by the accuracy of directions from Google Maps - even for Tier-2 cities in India (something that is not possible sans the GPS location info while using the online version). I believe Google Maps also uses the nearest cell tower info. So, give it a shot.
Nokia Securewave is a free security application and service that can be installed on select Nokia models. They claim that it can be used to remotely lock your cellphone in the event of loss and render the data useless to the thief. It allows you to archive the data (backup) on to their server and retrieve it when needed. It also lets you track your cellphone and notify your trusted alternative contact in case some one tries to insert a new SIM card.
Nokia India has also released some free applications for Nokia 5800. I found their Cricinfo Widget to be quite useful!
I’ll update this post as and when I find some handy tools.
Disclaimer: There are quite a number of tools available out there. I am only covering tools that are of interest to me.