Desktop file for WeeChat. Place it in ~/.local/share/applications. The --class parameter and StartupWMClass key allow WeeChat to have a proper icon separated from gnome-terminal (e.g. in the Unity launcher). Also included the notify.py plugin to make the icon vibrate when mentioned.

notify.py

# Author: lavaramano <lavaramano AT gmail DOT com>
# Improved by: BaSh - <bash.lnx AT gmail DOT com>
# Ported to Weechat 0.3.0 by: Sharn - <sharntehnub AT gmail DOT com)
# This Plugin Calls the libnotify bindings via python when somebody says your nickname, sends you a query, etc.
# To make it work, you may need to download: python-notify (and libnotify - libgtk)
# Requires Weechat 0.3.0
# Released under GNU GPL v2
#
# 2010-02-20, Aron Griffis <agriffis@n01se.net>
#     version 0.0.5: Add nick_separator, don't call show_notification twice on
#     privmsg, fix spelling s/nofify/notify/, use nick as "summary" for privmsg
#     notification, fit in 80 columns, tweak vim modeline.
# 2010-01-24, David Rubin <davidrub+weechat@gmail.com>
#     version 0.0.4.2 Fixed issue with self notifications when used with out "smart_notification"
# 2010-01-19, Didier Roche <didrocks@ubuntu.com>
#     version 0.0.4.1: add private message sender name
# 2010-01-19, Didier Roche <didrocks@ubuntu.com>
#     version 0.0.4: add smart notification:
#     be notified only if you're not in the current channel/pv window (off by default)
# 2009-06-16, kba <unixprog@gmail.com.org>:
#     version 0.0.3: added config options for icon and urgency
# 2009-05-02, FlashCode <flashcode@flashtux.org>:
#     version 0.0.2.1: sync with last API changes

import weechat, string, subprocess

weechat.register("notify", "lavaramano", "0.0.5", "GPL", "notify: A real time notification system for weechat", "", "")

# script options
settings = {
    "show_hilights"      : "on",
    "show_priv_msg"      : "on",
    "nick_separator"     : ": ",
    "icon"               : "/usr/share/pixmaps/weechat.xpm",
    "urgency"            : "normal",
    "smart_notification" : "off",
}

# Init everything
for option, default_value in settings.items():
    if weechat.config_get_plugin(option) == "":
        weechat.config_set_plugin(option, default_value)

# Hook privmsg/hilights
weechat.hook_print("", "irc_privmsg", "", 1, "notify_show", "")

# Functions
def notify_show(data, bufferp, uber_empty, tagsn, isdisplayed,
        ishilight, prefix, message):
    """Sends highlighted message to be printed on notification"""

    if (weechat.config_get_plugin('smart_notification') == "on" and
            bufferp == weechat.current_buffer()):
        pass

    elif (weechat.buffer_get_string(bufferp, "localvar_type") == "private" and
            weechat.config_get_plugin('show_priv_msg') == "on"):
        show_notification()

    elif (ishilight == "1" and 
            weechat.config_get_plugin('show_hilights') == "on"):
        buffer = (weechat.buffer_get_string(bufferp, "short_name") or
                weechat.buffer_get_string(bufferp, "name"))
        show_notification()

    return weechat.WEECHAT_RC_OK

def show_notification():
    subprocess.call("wmctrl -i -r $WINDOWID -b add,demands_attention", shell=True)

# vim: autoindent expandtab smarttab shiftwidth=4

weechat.desktop

[Desktop Entry]
Encoding=UTF-8
MultipleArgs=false
Terminal=false
Exec=gnome-terminal --disable-factory --sm-client-disable --class=WeeChat --maximize --execute /usr/bin/weechat-curses
StartupWMClass=WeeChat
Icon=chat
Type=Application
Categories=Network;IRCClient;
StartupNotify=true
Name=WeeChat
GenericName=IRC Client