I didn't see Virgin Mobile was supported.
For the US, to send a text message to a Virgin Mobile user, it's firstname.lastname@example.org
I joined this community to find out if I can receive text messages on my USCellular cell phone. I have a plan that allows me to send and receive messages free of charge, so I know I can use it. I just didn't see 'US Cellular' listed as a provider. Mine accepts cell phone to cell phone messages and I can only check messages via the phone. (The phone is a Nokia 5165 model if that's important.)