Did
you know that you can edit a selection in PSP?
Besides modifying
the size or feathering of a selection with "modify",
you can also modify it in other ways.
What
if you want this selection to go at an angle other than 90°?
Go to "Selections" and click on "Edit Selection"
Then
your selection will look like this 
Now
do what you want with the selection. For example, turn
it with the deform tool. 
Then
go back to "Selections" and click on "Edit Selection"
again.......
The result will be a selection going this
direction: 
In the following example, I used a freehand selection and then altered it with the "edit selection" by pushing the red edit selection with the "warp brush".
resulting in this change in the selection. 
Copyright
to Holder, 2006
http://www.glhold.com/tut/editselectiontut/editselectiontut.html