[gentoo-user] WPA Supplicant

I'm trying to get wireless working reliably on my laptop.  I have followed the documentation, but still have a lot of questions . . . especially since it only seems to work sometimes.
 
First, I'm using WPA Supplicant without the gui tools.
 
Second, I'm in NYC and there are a lot of networks I can use around town.
 
Third, Is there a way I can control the services I use from the Grub menu?  Since the laptop has a wireless card and an RJ45 jack, I'd like to be able boot and not use one or the other.  Since I know if I'm not physically connected to a network, there's really no reason to even try eth0.
 
Forth, The problem.  I'm not sure how wpa_supplicant works or how it should work.  The wpa_supplicant man page gives a few examples on how to run it, but when I look at the process list it seems to be run by another program called wpa_cli.  There's also a shell script in /etc/wpa/supplicant that looks like it can start or stop it with CONNECT or DISCONNECT.
1) Do I need to enter networks in wpa_supplicant.conf or does wpa_supplicant scan for networks and connect to whatever's available?
2) If I have multiple networks available how does wpa_supplicant choose which to connect to and can I specify which one I want?
3) How should wpa_supplicant be started, stopped and restarted?  What should be used for this:  wpa_supplicant, wpa_cli, or wpa_cli.sh?  I don't see anything in /etc/init.d for that, but it looks like netmount may be doing it.
4) The documentation doesn't say to, but the way I got wireless working is by creating a link net.wlan0 -> net.lo in the /etc/init.d directory.  Is this correct?  I think that's why it's starting automatically when I boot too, because I never added it with rc-update so netmount must be picking it up.
5) This is the most puzzling thing.  When wpa_supplicant starts even though I get a inet address I can't always get to the internet.  Why does the panel applet says I'm connected and ifconfig shows an inet address but firefox and ping can't reach a site like yahoo or google?
6) For networks where I have a password, should that go in wpa_supplicant.conf as plain text or should it be encrypted?
 
I think I have more questions, but this is good for starters.
 
Thanks,
 
dhk