I needed to get both USB and TCPIP working for ADB (don't ask), so I did the following (using directions others have posted from xda-developers)
Using adb shell:
su
#Set the port number for adbd
setprop service.adb.tcp.port 5555
#Run the adbd daemon *again* instead of doing stop/start, so there
#are two instances of adbd running.
adbd &
#Set the port back to USB, so the next time ADB is started it's
#on USB again.
setprop service.adb.tcp.port -1
exit
