internetseer.com

[polestar]

Do you use InternetSeer?

It checks your site every hour, and e-mails you if it's down.

It's quite good for comparing your sites on different hosts.

Are there any (better) free alternatives?

http://www.internetseer.com

[d99janh]

I use it, however I got bored by reading alarming mails about my
page being down (it´s on f2s.com ;) ), so I stopped reading them :D

I have not heard about any simular service (at least not a good one)

[ebird]

qwkmon.com

[LastActionHero]

1stwarning.com is good too. Qwkmon is good but the site itself is down sometimes! :p