What is the best option to open .docx, pptx files in Ubuntu LTS 8.04 ?

[Ashish Vijaywargiya]

Please help me in this matter because I need any converter or
supporting open-source software that help me on this matter.
May be this question has been asked so many times on the Ubuntu
mailing list but I don't know how to search the old email that
has been answered.

Please let me know if any search engine or place exists where I can
search old emails.

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Ashish Vijaywargiya
Indore (M.P), India
http://en.wikipedia.org/wiki/Indore