ok, slow down. I'm not familiar with Linpus, but that should be okay. First off, the interface is made for people who don't like interfaces. A little too simple for me. Are you in Simple mode or desktop mode?
For linux, when you are downloading from a browser, it is probably going to your home directory. That'll be in... /home/YOURNAME.
Linpus uses apt-get, so if you used that to download GIMP (apt-get install gimp), it should be automatically installed. You may have used synaptic to do this as well. You can open a terminal window and type gimp (or something like that) to run it. Of course, I don't know where the terminal window is in Linpus.
If you want a more traditional feel, use ubuntu or kubuntu. They're wonderfully supported and work well on laptops. Here's a link I found on another forum site...
Should help you. Just remember, if you install ubuntu and you don't like it, you can always reinstall linpus. I would suggest you give it another chance, though. Poke around for GIMP. Linux is a learning experience!