If you don’t mind reading the books online there are some free EBooks from APress up on their site.

A Programmer's Introduction to PHP 4.0
Dissecting a C# Application: Inside SharpDevelop
Writing Perl Modules for CPAN
Programming VB .NET: A Guide For Experienced Programmers
COM and .NET Interoperability

http://www.apress.com/free/index.html

--Brendon Schwartz