Can I delete photo stream pictures to clear iCloud storage space?

[iMore Question]

If I delete selected pictures from my Photo Stream on my iPhone, will they be removed from iCloud, and thus make room in my free iCloud 5gb of storage to backup new photos?
Also will this action delete them from my PC's synced Photo Stream folder?

I've read that PhotoStream is not supposed to effect your icloud storage, and that you get 1000 pictures, from the last 30 days for free, but this is not the case for me. I have pictures that are years old and am now out of iCloud storage space.

 

[SwitchBeach]

Your Photo Stream is not backed up to your iCloud backup. Only your Camera Roll is.

iCloud: iCloud storage and backup overview

Note also that you can now get 20 GB of iCloud storage space for $0.99 (US dollars) per month.