The first steps are pretty obvious: 

• acknowledging receipt of an application, 
• avoiding postings that say little or insult the intelligence, 
• eliminating out of date postings,
• monitoring an application against open opportunities, 
• staying in touch with relevant information, 
• letting the candidate know when their application is going to be flushed from the system,
• having a privacy policy,
• providing material that is interesting to candidates,
• eliminating unnecessary 'clicks',
• making sure the website runs quickly,
• offering suggestions to those who most likely are never going to be working for you,
• describing the hiring process (how long, what's involved),
• illuminating the culture with profiles of successful members of the workforce,
• addressing known PR problems (Here at Enron, we have a renewed emphasis on ethics),
• having a clear and compelling message,
• eliminating things that waste a candidate's time,
• providing ways for candidates to build their networks,
• and so on.

Getting today's website right can be the beginning of a new era for the recruiting function in your company.