http://www.linspire.com/lindows_products_license.php
"As discussed above, parts of the Linspire product are licensed under the GPL. Linspire fully supports the use and redistribution of those parts of Linspire which are covered under the GPL. There are, however, also 3rd-party components in Linspire which are not GPL (installer, CNR Technology, fonts, spell checker, Flash, Java, etc.).
Those who have obtained a copy of Linspire can find the source code for any of the GPL portions of Linspire in their my.linspire account or on the computer if they purchased Linspire pre-installed on a new computer. These individuals are free to modify and redistribute those GPL portions of Linspire found there. To honor our trademark and to avoid confusion among Linspire customers who wish to obtain a full and complete copy of Linspire, such products should not be called "Linspire," since they would be a different product (since they wouldn't have the non-GPL licensed parts, Linspire support, etc.)"
In other words, since there are some non-open source parts to the operating system, they can sell those pieces without needing to release source code. I don't know what exactly those pieces are; whether they're binaries that are legally licensed elsewhere and can't be GPL'd, or if they're drivers that companies gave them which they wouldn't for linux.
