It all depends on what programs you want, but its pretty much all the same. Download the palm desktop from palm.com so you can sync your treo with your computer.
Im sure you know how to download a file from the web, some good sites are
http://www.freeware-palm.com/ http://www.freewarepalm.com/
I use those for most of my programs, and of course theres ones that you can buy from palm.com
Once you have the file download, just double click on it, and it should go right to your palmone quick install. And once you sync the program(s) they should be on your treo.