Yes, absolutely.
yes
Yes, OpenOffice is compatible with Microsoft Office. It can open and edit the file formats used by Microsoft Office, allowing you to easily transition between the two programs. Additionally, Microprokey .com is a great website which contains tutorials and resources to help you work with both programs.
Yes. DOCM is a Word Microsoft Office Open XML Format document. It is opened by default by Word 2007 upwards. For earlier versions of Word (2003 and below), you'll have to download the Microsoft Office Compatibility Pack for free from Microsoft's website.
No, software is rarely 'backwards compatible' - Office 2007 should be happy to work with version 2003 files, but Office 2003 will likely reject 2007 files, due to it not being capable of understanding enhancements made after the Office 2003 software was written.
DOC - is a text document that can be opened and edited with MS Word or OpenOffice. RAR - is an archive that can be opened with an archiver tool, B1 Free Archiver foe example.
First you would have to have Microsoft Publisher in order to view or edit .pub files. The program Microsoft Publisher can be opened by going to Start->All Programs->Microsoft Office->Microsoft Publisher.
If the document from the Mac has been saved in a format recognised by Word then it can be opened by Word. There are variations in different versions of Word which means that sometimes even Word cannot open a Word document.
since XLS and XLSX are proprietary formats of Microsoft products, I'm not sure there is a (free) PHP way to do so. you can export your data in CSV, which is easily opened in Microsoft Excel or OpenOffice Calc
Microsoft Office 2010 installs plugin in Firebox web browser which allows documents to be opened directly from web browser into the appropriate Office desktop application.
PUB must be opened in a publisher software, without Office you could use a similar program like OpenOffice. If not you will need to converted to PDF or DOC with a third party software.
Normally it will update automatically. If it is linked into another document, it may have to wait until it is that document is opened before updating.
The Office button in PowerPoint 2007 (and all Microsoft Office products) is found in the top left corner of the presentation window once it is opened (see the image to the right).