This one-liner will output a list of installed programs, similar to what you get when looking it up through Control Panel → Add/Remove Programs.

Get-WmiObject -Class Win32_Product | Select-Object -Property Name

The advantage of this cmdlet is that you can dump it to a text file:

Get-WmiObject -Class Win32_Product | Select-Object -Property Name > Software.txt

And through PS remoting, you can also run this on remote systems.