Certifications are a valuable item in this economy, and are useful to bolster and reinforce a background in supporting your chosen environment.
There are a number of certifications, both in type and in provider:
- HP Certifications (including HP-UX)
- Red Hat Certifications (including RHCT, RHCE, RHCA, and others)
- Solaris Certifications (including SCSA and others)
Of course, there are many others. One very good source for quite a few certifications in a broad range of areas is Brainbench. The Brainbench certifications are excellent, but I wouldn’t let that stop you from going for the software developer’s certifications either – get both.
Once you have earned your certifications, you can put them on your wall or in your résumé – or both. The certifications will help, though they are only one of the items that interviewers will look for: most important is hands-on day-to-day experience. However, certifications help give you an advantage over the competition. Go for it!
UNIX Administratosphere 
I really hate certs. Only a few of them hold any real value. Once people started cheating (brain dumps) a lot of the certs lost their value. Now with no experience you can pass a test through rote memory. IMO they are only as valuable as the experience you have acquired on the job.
I’m interested in going ofter some certs, not because I can prove the depth of the things I know but so that I can corroborate the breadth of my knowledge.