Do you keep an archive of "useful" R code? and if so - how?

Hello Marc and Jeff,
Thank you for replying.

I am using winXP, and any recommendation for GUI based system will be
welcomed.

However, my initial question was not how to maintain code that I write
and develop, but rather how to keep a "filing system" for other peoples code
that I find useful.
Here are some simple examples:

? - A code to allow me to start a window with "history" recording turned
? on.
? - A code to have wider margins so to allow more space for the plot
? labels.
? - A code for creating an ellipse plot of a matrix of correlations.

All of these example are things I wouldn't put into a Subversion system or a
new package.

I just use plain text files for keeping notes - generally each project
directory I work on has a 'notes.txt' file which is a working log of
what I'm doing. If I think 'how did I do that the other day?' I can
search my text files.

 Recently I've been experimenting with using 'personal' or 'desktop'
wiki systems for this. Like Wikipedia but just for you, and stored as
files on your PC, and edited with a local client program instead of
over the web (although some personal wikis work over the web). I've
found 'zim' to be pretty good for this. It organises notes, lets you
link pages, timestamps things, has various plugins and MOST
importantly it's Open Source so you won't ever have your notes locked
up in a proprietary format that you need to keep paying a license fee
for.

 Not sure if there's a Windows port of it, but I'm certain similar
systems exist for Windows.

 Another idea is to have a public blog for R tips and tricks. That way
not only do you get free storage (from blogspot.com or some other blog
provider) but also it's searchable and other people can find it and
comment and improve on it.

 Or you could contribute to the R-wiki:

http://wiki.r-project.org/rwiki/doku.php?id=tips:tips

Barry