Here is how to run Afloat in Snow Leopard:

http://satukubik.com/2009/10/06/running-afloat-on-snow-leopard/

@norz

here is a link to the last compatible version of afloat for 10.4:

http://afloat.googlecode.com/files/Afloat-v31.dmg

it's still working great on my mbp running 10.4.11.

I love it!!

Opening this dialog at random times instead of when the user is actively using it is really obnoxious, so I didn't wait for a second dialog before uninstalling it - the "Maybe later" button made it clear that I'd be seeing this dialog pop up at random again, probably ruining a movie or a game.

The donation nag should appear twice and no more. If this doesn't happen, it's a bug and you should contact me -- it's obviously something I want to fix.

Nagware, not freeware.
Every so often this plug-in will open a "please donate" dialog (even if you're not currently using its functionality), possibly at very inconvenient times - I uninstalled it for this reason.

Does anybody have the 1.0b3, that seems to work well with 10.4 please?
(It doesn't seem to be available for download anymore.)

http://infinite-labs.net/afloat/ has a pubic beta of Afloat 2 for Leopard going on right now. Due to abuse (I won't name names in their entirety, cough*mac*cough*ate*cough) registration is required, but it doesn't take long.

Apparently if you use 1.0b3, ctrl-click, click "Show Package Contents," and drag "Afloat.bundle" to your SIMBL directory (/Library/Application Support/SIMBL/Plugins/), you will be able to use Afloat on Leopard. Make sure you have the latest version of SIMBL. For some reason, it doesn't seem to be working for me.

This is a great app, but is not working under Leopard unfortunately.