One day, everything was going great. There were some standard software updates that day, which I installed. The next day, NetworkManager Applet said that there were no network devices found. My Intel PRO/Wireless 3945ABG is showing up in the network card section of YAST, but nothing is showing up in ifconfig/iwconfig besides loopback. I keep playing with YAST settings and rebooting, but no go. Any ideas?

Welcome to LQ. Have you tried opening a console session and running
which will bring up the eth0 interface and start dhcp. If that doesn't work, please post the results of running 'lspci' as well as 'ifconfig'

"ifup eth0" gives me "Interface eth0 is not available". ifconfig gives me nothing but loopback. ispci gives me "command not found". What is ispci supposed to do?

I read your post again, and I noticed that I was typing ispci and not lspci. lspci says the following about my wireless card:

02:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)

And everything else:

00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT Express Memory Controller Hub (rev 03)
00:01.0 PCI bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT Express PCI Express Root Port (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 02)
00:1c.2 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 3 (rev 02)
00:1c.3 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 4 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #3 (rev 02)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #4 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) Serial ATA Storage Controller IDE (rev 02)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 02)
01:00.0 VGA compatible controller: nVidia Corporation Unknown device 0398 (rev a1)
02:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. Unknown device 8168 (rev 01)
06:00.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host Controller (rev c0)
06:04.0 CardBus bridge: ENE Technology Inc CB-712/4 Cardbus Controller (rev 10)
06:04.1 FLASH memory: ENE Technology Inc ENE PCI Memory Stick Card Reader Controller (rev 01)
06:04.2 Class 0805: ENE Technology Inc ENE PCI Secure Digital Card Reader Controller (rev 01)
06:04.4 FLASH memory: ENE Technology Inc Unknown device 0551 (rev 01)