I want to learn how to use XMPP and to create a simple web application with real collaboration features.
I am writing the application with Python(WSGI), and the application will require javascript enabled because I am going to use jQuery or Dojo.
I have downloaded Openfire for the server and which lib to choose? SleekXMPP making trouble with tlslite module(python 2.5 and I need only python 2.6).
What is your suggestion?
I have found a lot of issues with Openfire and TLS are not with the xmpp lib :( -- SleekXMPP in the trunk has been converted to Python 3.0 and the branch is maintained for Python 2.5
Unlike Julien, I would only go with Twisted Words if you really need the power of Twisted or if you are already using Twisted.  IMO SleekXMPP offers the closest match to the current XEP's in use today.
Best XMPP Library for Python Web Application