Lotus Sametime 9 does not open chat window

At my work we use Lotus Notes 6.5 for our email, meeting scheduling and instant messaging. I can't stand the horrible UI, buggy meeting scheduling and overall '90s feel when using it and would love to replace it with open-source alternatives.

So far I've been able to setup Thunderbird for email, and I should also be able to configure pidgin to do IM, but I can't find any replacement for the meeting scheduling. I need to be able to receive meeting requests and respond to them.

I've looked around trying to get the Thunderbird plugin Lightning to manage the scheduling, but everything I've read so far requires me to export .ics files from Lotus Notes or otherwise keep Lotus Notes around for day-to-day activities.

I've also looked into using Evolution as the client, but I found even less information for it than I did for Thunderbird.

How can I easily send, receive and respond to Lotus Notes meetings using an open-source alternative?

Alternatively, if there exists a full drop-in replacement to Lotus Notes I would also consider it.

Note: My desktop at work is a Windows XP machine, though I wouldn't be opposed to a solution requiring cygwin at this point.

Edit: I have no power over the server. I only want a compatible client.

You could try Notes 8.5 on a 90-day basis and make your IT guys jealous, so they'll move ahead with installing it.

http://www.ibm.com/developerworks/downloads/ls/lsndad/?S_TACT=105AGX28&S_CMP=TRIALS

Why are you still using Lotus Notes 6.5(0)? Version 8.0 was released 2 years ago. Version 7.0.2 introduced iCal support.

I don't know if 6.5 supports it, but there's a web-access mode. Perhaps you can convince your server admins to enable the feature, then you could use a web browser to access calendaring.

Unfortunately, Enterprise groupware packages like Exchange/Outlook and Domino/Notes see Calendaring as this panacea of awesome (rightly so), and they protect access to the server from just about anything but their own clients. Open Source Software historically has been very poor at accessing the servers for Calendaring functions. Obviously email and contacts are widely supported across a number of third party programs.

Not the answer you're looking for I'm sure, but unless you can convince your organization to upgrade to a newer version, or convince the admins to enable web access, you're stuck with the Notes client bloatware if you want calendaring.

Edit:

I know the policies in IT organizations can be prohibitive to your productivity, but it's a cost issue. You'll need to build an argument for upgrading Notes to management of the IT staff, show what kind of business value you (and others) might gain by upgrading the system. Groupware is a huge ordeal in large organizations (I'm assuming large, small companies don't use Notes usually), so this will require financial impact benefits that far outweigh the cost of migration and downtime.

We use Lotus Notes in our office (over the last few years upgrading from 6.x to 8.x) and I have used Evolution and Kmail at home (linux). Evolution is a bit more reliable than Kmail, but both have nearly the same functionality as far as email is concerned:

1. I use IMAP to get mail off the server. I used to use pop.
2. Never had an issue sending or receiving mail, with either protocol.
3. I can reply to meeting invites, but I can't invite others to meetings using the Notes calendaring features.
4. Meetings I've accepted go into my calendar without a hitch & do the usual alerting when they are due.
5. Email search may actually be better in the linux clients.

I have to agree with @jtimberman - if you can convince your company to move to Notes 8, you'll be happier - uses iCal which is compatible with many open email clients, which will definitely solve your meeting notification problems.

I know Evolution is available for windows, but I have never used it.

I've used spicebird for email/calendar/task (outlook replacement), it worked pretty good but I eventually went back to Outlook only because of it's UI. There was nothing wrong with Spicebird's I just like Outlook's better. I did like it's dashboard features where you could put RSS feeds.

http://www.spicebird.com/