KeepAlive.aspx is an interesting little file.  If you open it and leave it open in your browser it'll use an HTTP refresh every so often (can't remember the interval) to refresh your site and thus keep it alive.  Alternatively, you can configure a KeepAlive service to access that file (or your Default.aspx) every 'x' minutes to achieve the same effect.  The one thing to note, however, is that even using a KeepAlive service against a shared-hosting DNN site you aren't guaranteed to keep it alive because they (the host) have ultimate power over AppPool recycles (in other words, they can force it to recycle every 'x' minutes even if it is actively in use).

There are various options out there, some free, some not.  I wrote a simple little utility some time ago that installs as a Windows service on your computer and can be configured to hit any number of sites you want.  Like I said, it is really simple so don't expect anything fancy out of it (like notifications if it is down or anything).  Available on my personal website here: http://foober.homeip.net/Development/DotNetNukeModules/tabid/213/Default.aspx

Others I noticed in a quick google search:

• TMMWorld
• Mitchel Sellers' site MyWebKeepAlive.com (he is still working on it... view his blog post here)
• Keepalive Pro
• BlueTango
• KeepAliveForever

There are plenty others like pingdom, etc.

Sorry guys been away for a couple of days

Thanks for advice but I really need something that I can run on my shared hosting space as its not practical for me to fire it from my own machine.  This is a client that is asking.#

Cheers