I am looking for information on the Internet market in Vietnam.
If you haven't already been using the library's International Business Research Guide, I will point you there first. Under the Country Resources tab, there may be a few databases that can help with your question. I tried MarketLine Advantage first and did a country search for Vietnam. You should get the Country Analysis Report: Vietnam, In-depth PESTLE Insights. In the right hand column you will see a link for Technological Landscape. There is a Telecommunications and Internet section that will tell you how much of the country has internet access.
MarkeLine Advantage also has an industry report for Telecommunication Services in Asia-Pacific, but it doesn't specifically mention Vietnam. If you think this report would still be helpful, you can search MarketLine Advantage for: telecommunication services. Then click the link in the right column for Asia-Pacific. You should then see a link for Asia-Pacific - Telecommunication Services. To see the full report, you need to click on the "Download full Report" link. This is a large file, and it may take a while to download.
Also, the International Telecommunications Union has statistics by countries at http://www.itu.int/en/ITU-D/Statistics/Pages/stat/default.aspx (look under the Time Series by Country heading).