I am looking for a good company who has some online domain/ site alarm system… something like… the system must capable of alert me via SMS (US, Europe and Sri Lankan cellular network must be compatible), email or pager me, when my site/s, server goes down.

Can someone suggest me one?

What we are looking for is:
1. an sms alert system as soon as one of our sites or servers go down

2. multiple recipients with worldwide reception to wherever GSM mobiles operate

3. monitoring should be done preferably from UK but not limited to. Sri Lanka and US should be excluded.

I think you can do this yourself with a product called What's Up Gold by IPSwitch. www dot ipswitch dot com (can't post URL's yet).

This product is easy to setup, will send alerts via e-mail, SMS, I think even call your cell through a modem and provide voice alerts, etc. We use it to monitor client servers and provide the services you're requiring. It will run fine on a WinXP system but I recommend a redundant server of course.

Hope this helps.