As planned for today, the Microsoft officially retired Windows XP mainstream support. However, extended support will continue till the year 2014. One would wonder, what are the differences between mainstream support and extended support? Well, there are not much. Both offer (free) security updates and phone/web support to the users. However, after today, any new bug-fixes or updates will require extended support contract.
Also, this effects all the versions (excluding Windows XP Embedded). Since, there are not any problems to be solved with the XP (except security holes), we do not need to worry about anything for our netbooks. However, it is encouraged to update to new version of windows (I recommend Windows 7).
Note 1: If Microsoft releases SP4 too, it will retire support for SP3.
Note 2: this deadline is also valid for Office 2003