I think I figured this out. The root of the problem was the wireless_tools dep file. It had wireless_KERNEL.tcz in it. When I did tce-load -wi wireless_tools.tcz, the process jammed up when it couldn't find wireless_xo1-20100728.1841.1.olpc.a0a0edb7d8cbadb.tcz. The xo1-20100728.1841.1.olpca0a0edb7d8cbadb is the kernel name. I ran uname -r and that's the result I got. I think I have some kind of unusual set up that allows Tinycore (microcore in my case) to run on an OLPC XO computer. So now (I think) I understand the cause. The solution I discovered before understanding the cause -- simply delete the problem line from the wireless dep file (it's the only line so you end up with nothing in the file). Then I was able to tce-load -wi wireless_tools.tcz, and after that was able to get wpa_supplicant.
The next surprise, though, was that wpa_supplicant wouldn't work per the instructions. The wpa_passphrase worked fine, and I wrote the config.conf file with the long psk number I got from passphrase, but wpa_supplicant didn't run right. I got several error messages.
I gave up on trying to connect from the command line and installed wicd. Of course what I learned about getting wireless_tools and wpa_supplicant installed on an XO was necessary, as it turns out, since they are both needed for wicd. My boot time now, with microcore + chromium browser + wicd is still under 40 sec, so I think I got what I need at this point. Again, thanks for helping me.