There is a lot of GPS software available on the internet, most software available is commercial but there are also many that are not. Much of the free GPS software available is shareware, meaning that you don’t need to pay for them but as with all free software there is no support or documentation. Also finding updates for some of these is difficult.
Now there are two kinds of free software Shareware, freeware (are the same) and trial. The trial version is not really free because most of the features are disabled and you have to pay to enable them. However it will give you a good insight into how the software works and if you can really use it.
Be sure to search for free software that is compatible to your operation system, if it’s a PDA find out if it’s a Windows CE or Palm operating system. Also check if the software you are about to install has any compatibility issues with the software that you already have. There is a lot of free GPS software out there but be sure the software does not have spyware hidden in it or this could cause you more pain than you would like.