Microsoft will be closing its public beta programme for Vista today. Users who want to participate in the beta test have until 30 June to download a copy before it is withdrawn from Microsoft's website. 

The Vista public beta programme was launched earlier this month and demand for the 3.5GB download was so great that Microsoft had to restrict access after fears that it could bring down the internet. 

Ian Moulster, product manager for .Net platforms at Microsoft, said on his MSDN blog that users should start the download today, even if they don't complete it.

This will allow them to continue the download after the cut-off date, at least until 14 July. 

It is also important that users obtain a product key and activate their copy of the beta, and Moulster promised additional benefits to those that activate.

"We may be able to provide people who have activated copies with future stuff. I'm being vague because I need to be. Just trust me and make sure you activate," he wrote.

Moulster also recommended users to get the software from Microsoft's MSDN Beta Experience website as this allows the company to "provide users with future developer-related content".