I have the similar problem with oneiric.1. login
2. ps axw|grep ibus
 4194 ?        Sl     0:00 /usr/bin/ibus-daemon --xim
 4200 ?        Sl     0:00 /usr/lib/ibus/ibus-gconf
 4202 ?        Rl     0:35 /usr/bin/python /usr/share/ibus/ui/gtk/main.py
 4204 ?        Rl     0:34 /usr/lib/ibus/ibus-x11 --kill-daemon
 4256 ?        Sl     0:00 /usr/lib//ibus-sunpinyin/ibus-engine-sunpinyin --ibus
 4836 pts/0    S+     0:00 grep --color=auto ibus

 the ibus icon did not show in the upper right pannel and there was no input method.  But the process:
 4204 ?        Rl     0:34 /usr/lib/ibus/ibus-x11 --kill-daemon
occupied almost 100% cpu.

3. I killed the process:
 4204 ?        Rl     0:34 /usr/lib/ibus/ibus-x11 --kill-daemon
and 
 4202 ?        Rl     0:35 /usr/bin/python /usr/share/ibus/ui/gtk/main.py
in htop

4. then I pressed Alt+F2 run 
	ibus-setup
5. I pressed ok when a dialog pop-up saying the ibus-daemon was not running and it would start a ibus-daemon.
6. ps axw|grep ibus
 4194 ?        Z      0:04 [ibus-daemon] <defunct>
 4897 ?        Sl     0:03 ibus-daemon --xim
 4898 ?        Sl     0:00 /usr/lib/ibus/ibus-gconf
 4900 ?        Sl     0:01 /usr/bin/python /usr/share/ibus/ui/gtk/main.py
 4902 ?        Sl     0:00 /usr/lib/ibus/ibus-x11 --kill-daemon
 4907 ?        Sl     0:00 /usr/lib//ibus-sunpinyin/ibus-engine-sunpinyin --ibus
 4928 pts/0    S+     0:00 grep --color=auto ibus
now, the ibus icon showed in the upper right pannel, the input method worked fine, and cup occupation was normal.
7. logout
8. login, the same problem happened again as described in 1.

other information

1. lsb_release -d
Description:	Ubuntu 11.10

2. dpkg -l|grep ibus
ii  ibus                                   1.3.99.20110419-1ubuntu3                        Intelligent Input Bus - core
ii  ibus-gtk                               1.3.99.20110419-1ubuntu3                        Intelligent Input Bus - GTK+2 support
ii  ibus-gtk3                              1.3.99.20110419-1ubuntu3                        Intelligent Input Bus - GTK+3 support
ii  ibus-pinyin                            1.3.99.20110706-1                               Pinyin engine for IBus
ii  ibus-pinyin-db-android                 1.3.99.20110706-1                               Pinyin engine for IBus - Android database
ii  ibus-qt4                               1.3.1-1ubuntu3                                  qt-immodule for ibus (QT4)
ii  ibus-sunpinyin                         2.0.3-1ubuntu1                                  sunpinyin engine for ibus
ii  ibus-table                             1.3.0.20100621-3ubuntu1                         table engine for IBus
ii  libibus-1.0-0                          1.3.99.20110419-1ubuntu3                        Intelligent Input Bus - shared library
ii  libibus-qt1                            1.3.1-1ubuntu3                                  qt-immodule for ibus (QT4)
rc  libibus1                               1.2.0.20091215-1ubuntu4                         New input method framework using dbus
rc  libibus2                               1.3.9-0ubuntu3                                  New input method framework using dbus
ii  libusb-0.1-4                           2:0.1.12-18                                     userspace USB programming library
ii  libusb-1.0-0                           2:1.0.8-4                                       userspace USB programming library
ii  libusbmuxd1                            1.0.7-1                                         USB multiplexor daemon for iPhone and iPod Touch devices - library
rc  libusplash0                            0.5.49                                          userspace bootsplash library
ii  python-ibus                            1.3.99.20110419-1ubuntu3                        Intelligent Input Bus - Python support