Here's a powershell script that might be of use (I'm a novice at Powershell, but this is what it's good at...)
$a=get-date
$t=new-timespan -hours 1
$a=$a-$t
get-childitem -path t:\|where-object -filterScript{$_.LastWriteTime -le $a}|Remove-item
Basically, we load the current date/time into $a, then we create a difference value ($t) of 1 hour (this could be any timespan - you can set it down to the millisecond). So if $a is 10-9-2008 2:00 pm, after $a=$a-$t, $a will be 10-9-2008 1:00 pm. The last statement selects all files (get-childitem) from the designated path (t:\) - you can use wildcard (t:\*.txt) or regular expressions in the path parameter - the list of files is passed to the where-object, which filters out anything newer than $a - actually selects all files with LastWriteTime more than 1 hour ago. The filtered list is passed to Remove-item, which deletes all the files.
-Eric