Learn how to use Unix. If you already know Linux, you should still study any differences from Linux (eg. starting daemons in Solaris is with the svcadm command).
Setup a Solaris system on an x86 system with a Solaris x86 DVD. This platform will allow you to learn from the driver's seat.
Learn about Solaris zones, Sun's virtualization product for Solaris instances. It is very powerful and employers expect you to know everything about zones in your head.
Learn about Dtrace, a powerful suite of tools used to diagnose problems with programs running underneath Solaris. Dtrace will give you a huge leg up on other candidates, many of whom do not know Dtrace including Linux system admins and even some Solaris system admin.
Learn about zfs, Solaris's new filesystem. This is not commonly used but it's very easy to learn because the commands are few and easy to remember.
Study the SCSA and take both parts of the SCSA certificaiton exam. SCSA stands for Sun Certified Solaris Administrator which is THE certification for Solaris system admins. Take a course from an IT vocational school if you need help to pass the certification exam. As long as you study or take a class, you should be able to pass the certification test in one try. Because of the lack of real talent in Solaris from people who went to Linux, many employers may require a SCSA to verify that Linux experience isn't being substituted for Solaris experience. Both Linux and Solaris are SvsV derived, so commands are very similar. Get a SCSA certification to make sure employers know you're really a Solaris system admin.
Get a job as a Solaris system admin. Do this soon, because opportunities will open up as Oracle integrates Sun products with very profitable and expensive Oracle products.