Microsoft provides different levels of support for their products for varying periods of time depending on how they categorize the product.  For information about Microsoft's lifecycle support policies, go here

Most of the Windows XP family of operating systems (Home, Embedded, Media Center and Tablet) are considered to be consumer products.  As such, Microsoft provides mainstream support for 5 years after the product was released and self-help online support for 8+ years.

Mainstream support includes:

• Incident support (no-charge incident support, paid incident support, support charged on an hourly basis, support for warranty claims)
• Security update support
• The ability to request non-security hotfixes

Self-help online support includes:

• access to Microsoft's Knowledge Base articles
• access to FAQs, troubleshooting tools and other resources
• it does NOT include security update support
  

Windows XP Pro is considered Business class software.  As such, Microsoft provides mainstream support for 5 years after the product was released, extended support for an additional 5 years and self-help online support for 10+ years.

Mainstream support includes:

• Incident support (no-charge incident support, paid incident support, support charged on an hourly basis, support for warranty claims)
• Security update support
• The ability to request non-security hotfixes

Extended support includes:

• Paid support
• Security update support at no additional cost
• Non-security related hotfix support requires a separate Extended Hotfix Support contract to be purchased. Per-fix fees also apply.
• Microsoft will not accept requests for warranty support, design changes, or new features during the Extended support phase.
• Extended support is not available for Consumer, Hardware, Multimedia, and Business Solutions.

Self-help online support includes:

• access to Microsoft's Knowledge Base articles
• access to FAQs, troubleshooting tools and other resources
• it does NOT include security update support
  

Extensions - Consumer

So for the consumer versions of Windows XP, mainstream support was going to end on December 31, 2006 and there was no guarantee of any security hot-fixes beyond that time.  Microsoft has now extended the mainstream support deadline for the consumer versions to an undefined date that is two years after the release of the follow-on operating system.


Extensions - Business

For the business grade Windows XP Pro, mainstream support was also going to end on December 31, 2006.  Extended support would have kicked in at that time and been provided until December 31, 2011.  If there were any security issues requiring a hotfix, these would have been provided at no cost.  One would have hoped that such hotfixes would have also been made available for the consumer versions of Windows XP as well.  Non-security related issues would only be patched if you were willing to pay for them.

Microsoft has now extended the mainstream support deadline for the business version to an undefined date that is two years after the release of the follow-on operating system and they have extended the extended support deadline to an undefined date that is seven years after the release of the follow-on operating system (thus five years beyond the end of mainstream support).