[Xymon] Question: alternative(s) to sms/mms gateways

Question for the Xymon list:

What have you used, other than email-to-sms/mms gateway, to send xymon alerts to cell phones? I've been hit a few times with unreliable email to mms gateway (TMobile).

I know about pushover.net. Are there any others?

Thanks,

glauber