IF it is added using rc-update then restarting should not be a problem = loading at startup by defualt now. Did it also load the driver / module to make it to work ?
If the driver / module is there to make it work then use net-setup to get connection to wireless router if not already connected.
The Cisco Aironet 340 should show up as something else not as intel 100 I could be 100% wrong here.
Loading the pcmcia part you could get it working if not already loaded with "modprobe pcmcia" have to check on this not sure about name for pcmcia.
lsmod should list it if it is loaded as pcmciasomething or just pcmcia.
Installing the drivers.
You can download and extract the aironet .gz file using right click and "extract" option if using kde.
Might be able to skip the pcmcia compile part.
I can not think that the aironet is not yet in the kernel.
Will fire up the SL install and have a looksee maybe there is a easier way.