Website monitoring software that I can download?

[gu10214]

I was looking around for software that has the below capabilities:

• HTTP Requests as well as ping requests.
• Track Email server
• Track FTP as well
• Tracks and records down time.
• Emails me if and when there is downtime.

Is there such a program out there? I've been looking around and cannot make any decisions. YourSiteUp Pro, Alertra, Uptime 100 etc...

I have about 4 computers, one is my server that's constantly on, and I would like to install an application there to do this job.

Any advice/suggestions or reply with what you're currently using would be greatly appreciated.