The releases of Firefox come fast, and because some newer version can cause problems with addons (or TiddlyWiki saving/import) you might want to test them first.
This howto will guide you to a multiple firefox setup on your pc (performed on linux).

Step01

The releases can be found here:
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/

Step02

make a folder in your home directory
mkdir /home/YOUR_NAME/browsers
mkdir /home/YOUR_NAME/browsers/firefoxes
cd /home/YOUR_NAME/browsers/firefoxes 
(w)Get the versions you like (follow links in Step-01and pick your platform/versions)
wget ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/5.0.1/linux-x86_64/en-GB/firefox-5.0.1.tar.bz2
wget ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/6.0/linux-x86_64/en-GB/firefox-6.0.tar.bz2
tar jxvf firefox-5.0.1.tar.bz2
rename the unzipped firefox version
mv firefox firefox-5.0.1
extract the next version
tar jxvf firefox-6.0.tar.bz2
rename the unzipped firefox version
mv firefox firefox-6.0

Step03

Each version needs a separate user profile:
firefox -no-remote -CreateProfile firefox-5.0.1
firefox -no-remote -CreateProfile firefox-6.0

Step04

cd firefox-5.0.1
start firefox-5.0.1
./firefox -no-remote -P firefox-5.0.1
cd firefox-6.0
start firefox-6.0
./firefox -no-remote -P firefox-6.0

\o/
bag
howtoos_public
created
Fri, 02 Sep 2011 08:39:16 GMT
creator
bauwebijl
modified
Fri, 02 Sep 2011 08:59:15 GMT
modifier
bauwebijl
tags
browsers