GSM modem link

We are using electrical feeder monitoring units ( 486 based running QNX4.2)
currently linked to master control through land line modems. Can any body
suggest if GSM modems (WAP or just serial link) be useed. Are there drivers
available for GSM modems of any make. We have problems of reliability with
land line modems.
LRSUBRAMANYAN
seto@vsnl.com
lrs@vsnl.com