ComputerWorld reports that Acer is offering a free upgrade to Windows 8 on some ultrabook models

Acer will refund consumers who purchase the Aspire S3, Aspire S5, Aspire M3 and Aspire M5 ultrabook models between June 2 this year and Jan. 31 next year. Users will have to pay Microsoft for the upgrade, but will then be refunded by Acer via a claim website.

The offer is valid in 36 countries in Europe, the Middle East and Africa, but not in the U.S., Canada or other Asian countries.

  Acer to offer free Windows 8 upgrades on some ultrabooks