From my mail bag:
Where can I get free interactive access to HP-UX or Linux distro or UNIX shell access?
You can simply grab and try out any Linux / BSD / Solaris Live CD. However, some time you cannot install and use particular UNIX like os. So, if you want to try the latest technologies over the Internet? Try HP TestDrive program:
This program allows you to testdrive some of the hottest hardware and operating systems available today. Have you ever wanted to try out HP's exciting 64-bit Integrity and PA-RISC technology? Get time on SMP x86 and Opteron ProLiant servers? Try out a Blade server. Try different Open Source operating systems such as FreeBSD, Suse, Redhat, Debian and other Linux distributions.
This program is perfect for students and new users to try out and learn basis of UNIX. You can also try and test your C/C++ programs using latest Intel compilers. It is intended for those users who want to sample the 32- and 64-bit servers running a variety of HP, UNIX, Linux and third-party operating systems and applications.
=> HP Test Drive Program [hp.com]