Looking at my Xoom usage online today I noticed that there were 5 text messages sent to the phone number of the line my Xoom is using. But, as discussed in other posts here, the Xoom cannot receive or send text messages. I called Verizon to turn off the text messaging feature on this line and the rep told me that the text messaging feature is requried for the Xoom line, and it cannot be turned off or blocked.
So watch your first bill very carefully, you will probably be charged $0.20 for each text message even though you could not receive it.