tell application "Path Finder"
   set windows_list to every finder window
   get name of finder window 1
   get bounds of front finder window
end tell

tell application "Path Finder"
   PFOpen "/Users/<username>/Desktop" -- passing it a POSIX path
   open (choose folder) -- passing it an alias
   reveal (choose file) -- passing it an alias
end tell

Original post: http://blog.circlesixdesign.com/2007/01/18/textmate-in-pathfinder/

tell application “Path Finder”
    set selection_list to selection
    set ThePath to ””
    if the (count of selection_list) = 1 then
        set theItem to the first item of selection_list
        set ThePath to quoted form of (POSIX path of the theItem as string)
    else
        set file_list to ””
        repeat with one_item in selection_list
            set file_list to file_list & (POSIX path of one_item as string) & ” “
        end repeat
        set ThePath to file_list
    end if
    set TheCommand to “open -a TextMate  “ & ThePath
    do shell script TheCommand
end tell