Some PC users are too accustomed with the MS Word default page setup (8.5" x 11" page size, 1.25" margin on right and left sides, etc.) that sometimes they get annoyed by the default page in OpenOffice... A4 page size, .79" margins on all sides...
Also, I also found that not all new users to OpenOffice.org knows howto change their default page so let me share my way. I guess there are other means to do this and if you have one, just share it here. Here it goes:
Open OpenOffice Word Processor. You'll notice that the side margins are smaller than the default margins in MSWord. First, you have to format the page by clicking Format --> Page. Then click the drop down beside the word Format to choose Letter. The height and width settings will change accordingly to 8.5" x 11".
Change the left and right margins to 1.20". Personally, .79" top and bottom margins are ok for me. Click OK.
Now you have to save the page as a template. Click File --> Templates --> Save. Give a name to your template, let's use LetterDefault. Click OK.
Now we have to set it as default. Click File --> Templates --> Organize and then double click My Templates. There you see the template you have just saved (named LetterDefault), right click on it then left click on the Set as Default Template. Click Close and that's it!
Close OpenOffice Word Processor (you don't have to save the document you are using). Open it again to see if it works. I hope this helps.