Installation:
1. Download http://downloads.freenetproject.org/alpha/installer/selfextractpack.jar∞ [^]
2. Either try double-clicking on the jar or open a msdos prompt, cd to the folder to which it was downloaded and execute "java -jar selfextractpack.jar"
3. a installation dialog should pop up. Go through all steps and choose values that you like. If you don't know what a option means leave it alone, you can still change it later in the webinterface.
4. after the last step click on the now activated "install" button
5. It will start downloading jars and create config files but always fail at the end with an error because the installer is broken on win98. Click on the "Show details" page and look at the error tab, as long as it only complains about GUI elements and not being able to run "run.cmd" but did fetch the jars (see the "Output" tab) the installation did work.

Running freenet:
1. open a msdos prompt and cd to the "bin" folder in freenets folder.
2. execute "wrapper-windows-x86-32.exe -c ../wrapper.conf"
3. wait until the node started up and don't close the msdos prompt :)

Alternativly create a batch file somewhere and run that command (cd-ing to the right folder before or using absolute paths) inside the batch file, I wouldn't want to type it every time I want to run freenet.

Stopping freenet:
Either use the webinterface or go to the msdos prompt which runs the wrapper and hit ctrl+c. If you need to shutdown fast, hit ctrl+c multiple times.

Updating freenet:
Either use freenets update-over-freenet feature or download the files manually. The update script seems to be incompatible with win98. If you download them manually be cautious of the wrapper: It alternates between using either freenet.jar or freenet.jar.new and either freenet-ext.jar or freenet-ext.jar.new on each update over freeent, so replace both.
Freenet-ext.jar can be fetched from http://downloads.freenetproject.org/alpha/freenet-ext.jar∞ [^]
freenet.jar can be fetched from http://downloads.freenetproject.org/alpha/freenet-stable-latest.jar.url∞ [^] . If that url only downloads a .url file try downloading http://downloads.freenetproject.org/alpha/freenet-r*numer*-snapshot.jar∞ [^] , replacing *number* with the revision number of your choice.

Hope that helped, ask if something is unclear. :)

Someone should probably add this to the wiki but I don't feel like registering at yet another place.

Edit: stupid auto-detection of urls ...