Infact Links are the elements that help the site getting indexed. If you meant "getting links, before the domain goes live" then perhaps, you have to understand that links are the medium for visitor to come over your portal. If they follow it and find no site, now thats for sure wont leave a nice impression.. In general, Links will help your site being indexed and more so with the SERPS..go ahead get them
As soon as the site goes live get the links coming in. Like lovekills_s says this is the best method of actually getting the site indexed.
See it as linking in advance, as soon your site is live it will get indexed much faster because of the backlinks. You could also consider of hiring someone to submit your site to a bunch of directories.