Weechat 0.2.3-2 doesn't work on the WL500g out of the box, because there are some missing dependencies you might need to install:

ipkg install gnutls
ipkg install libtasn1
ipkg install libgcrypt

and finally:

ipkg install weechat

To start weechat run e.g.:

weechat-curses irc://nickname@irc.xxxxx.net/#channel

some commands that work:
/quit ->disconnects from server
/away message ->set away status
/away ->set available
/names ->show names