Free Alertra Equivalent

[Pete]

Hi... I need to start getting notified when sites I
host go offline - it's not very impressive for my clients if the first I hear about it is when they phone me.

Seems like Alertra would do this for me, but
I'd rather pay less or nothing at all. Can anyone recommend a good cheap/free service? Evidently, the uptime monitor needs to be reliable, so I am willing to pay
something...

I found a couple of free ones...
http://www.uptimeagent.com/
http://basicstate.com/

TIA.

[Jeewhizz]

siteuptime.com

[Pete]

Looks great -thanks.