navigation / location bar

Hi,

a lot of web sites propose a locationbar (something like dynamic map site)
to end user when they are browsing the website.
usually i looks like that:

Home > Products > Software > Operating System > Windows XP

User can come back to a previous parent node by just clicking on the name,
for example : Software.

so:
1. what is the best method to use to create such "location bar" ? (array
stored in session variable ?)
2. how to populate this bar ? (each time that user visit a page, the array
is updated. if yes, how ?)

--
Alain
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Windows XP SP3
PostgreSQL 8.2.4 / MS SQL server 2005
Apache 2.2.4
PHP 5.2.4
C# 2005-2008