Chris from the Boulder LUG pointed this out to me last night while I was singing the praises of Edit > Paste Special in OpenOffice.org.
Let's say you've got this data.
It's accurate, but you want the columns and rows in different positions. You want it flopped 90 degrees like this.
Here's all you need to do.
1. Copy the original data.
2. Choose Edit > Paste Special.
3. Leave All selected and select Transpose.
4. Click OK.
And there you are, with the whole thing flopped around the way you want it.
Now just delete the old data, drag the pasted data over it -- whatever you want.