There are still a couple that are not posted yet — I’ll update this post as they are added. –TR 
Test-driven Development meets design-by-contract
Jim Weirich, Compuware
URL: http://onestepback.org/articles/TddMeetsDbc
Google Ajax Search API
Mark Lucovsky
URL: http://conferences.oreillynet.com/presentations/os2006/lucovsky_mark.ppt
Driving Rails Deep into the back office
Obie Fernandez
URL: (URL hasn’t been posted yet — but should be soon)
Ruby and .NET
John Lam, ObjectSharp
URL: URL doesn’t appear to […]

Just a note — The presentation notes have been posted for all the presentations now (at least as far as I can tell). I’ll post another post with direct links to all the sessions I attended after this one.
KeyNotes
The first few keynotes really weren’t that interesting (I thought) and I’ll admit that I spent my […]

For those interested in seeing all the presentation notes from OSCON 2006, you can find all the sessions currently posted at: http://conferences.oreillynet.com/pub/w/46/presentations.html
For sessions that I’ve attended and written about, I’ve placed them below.  As more sessions become available, I’ll post additional links.
Building Internet Applications with Mozilla XULRunner
Benjamin Smedberg
URL: http://conferences.oreillynet.com/presentations/os2006/smedberg_benjamin.odp (Open Office files)
Google AJAX Search API
Mark Lucovsky
URL: http://conferences.oreillynet.com/presentations/os2006/lucovsky_mark.ppt
Handling […]

Keynotes:
The Zen of Free
Simon Phipps, Sun
“Opening” the Possibilities: APIs and Open Source
Gary Lang, AutoDesk, Inc.
Ugh — As good as the first day’s keynotes were — these were not.  I was nearly ready to bag the keynotes when…
5 a day
Robert “rOml” Lefkowitz, Root Markets
This was a fantastic keynote.  He started with a tomato and eventually wound […]

Test-driven development meets design-by-contract
Jim Weirich, Compuware
Slides: http://www.onestepback.org/articles/TddMeetsDbc
I enjoyed this session partly because I’m not a big fan of Ruby’s Unit Testing and liked the idea of a contract testing method.  The session discussed a separate testing packed called rSpec (http://rspec.rubyforge.org/).  I’ve included a link to the presentation which includes sample code on how one would […]

In the openning keynote, Tim O’Reilly presented what he calls his 5 big ideas about open source.  Some I thought were fairly interesting. 

Architectures of participation beyond software development (Web 2.0)
The idea here is that in this new world of Web 2.0, successful companies are looking to architectures where people build systems simply by using them.  […]