[Blind-sysadmins] Remote monitoring of systems/on call work

Hi, Very quiet here at the moment, and there are plenty of members. Just kicking off a topic which I have had to deal with recently. Has anyone used any remote monitoring/diagnostic software, that if a specific problem (possibly using an API to communicate with a bespoke application to trigger events) occurs, that it will email or send an alert? How successful have these been? The other issue, have any of you worked any on call system, and if so, how did you arrange transport to work if required? I am trying to avoid it now, but we may have to go down this road, using remote VPN where possible. Thanks. Andrew.