Having now been through more than one recession while covering technology (it's four by my count, although yours may vary) I have detected a pattern.
Spending drops to near zero, and customers spend the time learning to get more value from what they already own. (During the last recession Voice Profile for Internet Mail vendors sponsored a "vendor bake-off" using this Swedish Chef image in their logo.)
This was especially true during the dot-bomb, and it was reflected in productivity statistics. Economists expected productivity gains to go away once people could no longer afford new gear. In fact they increased.
So those expecting big things from the "PC Moment" of companies moving to open source during the current downturn may be disappointed.
It's true that many companies who would never have looked at open source before may now turn to it. But don't expect to see big checks resulting from that move. Not right away.
For instance, I can see a lot of companies deciding to ditch Microsoft Office and just download OpenOffice.org, which can handle recent Microsoft file formats. But that does not mean they will be writing checks. More likely they will just download it and pocket those savings.
Which leads me to a suggestion, one that could be taken up by the Linux Foundation and those in the open source business community.
The headline -- open source is not free. But the body of the piece describes other support you can provide open source, even if you can't afford to write a check right now.
As has been noted here before there are many things you can do for open source besides write checks. You can try beta code and deliver bug reports. You can contribute improvements you find yourself making. You can participate in forums for your software, and help train new users.
The main cost here is letting people outside the corporate firewall, even on company time. While they train others through a forum they also learn new tricks they can use at their desks. While they contribute bug reports they improve the quality of what they are using.
In other words you can pay for your company's use of open source software by having your users become true members of the open source community.
Later, when things get better, I'm sure those loyal employees may encourage a more direct form of showing your support. But even before then, ask what you can do for open source.