Sending those links to those instant link indexing services would work - if the content on the web2.0 is good enough, and normally these would get indexed within 24 hours.
However, the instant link indexing service doesn't last - your links may go missing from the index after some time.
For longer and lasting effect, using a link building tool and build links to these web2.0 would have a better retention rate for being indexed on the search engine. And if the links build have some link juice, those can be passed upwards as well - a win-win.