Here's my personnal experience. I have developed two years
ago a similar site. I was student, perl newbie,
apache intermediate, SQL newbie, XML very-newbie, good
knowledge of linux etc...
I had some technical knowledge in SQL, perl and so on, but no
concrete experience. My colleague and friend (student too)
was at the same level than mine.
We've spent 3 months full time plus 2 months coding during the night. And we went with a mod_perl (Apache::Registry)
site, XML & SQL data, Template system (HTML::Template)
This site was a rewriting of an older one (mod_cgi + msql
+ print $html; + no cookie + no session :)))
Finally, the site major features were : Job posting, Resume posting,
candidature system, application letter, Pro directory ...
I hope this help you to figure out the developement time,
but I guess that it depends on plenty of details... So the other
posts should be more precious than this one :)