It just depends. If you've got unique content it shouldn't take too long. Have you submitted an XML sitemap at Google webmaster tools? That sometimes helps speed things up. Also tweeting about my posts seems to help me with quicker indexing as well.
You can always ping your blog psot for quicker indexing or just tweet it or post a link on facebook than google will surely index it quickly
Well, It depends on your blog & content quality... you should share your blog post on social bookmarking sites like digg, SU etc. to be indexed your post ASAP.
If you are collecting quality backlinks & unique content to your blog then it will help you to get index faster