How long does it take to get listed in a Search Engine?
The short answer is that I have absolutely NO IDEA.
OK, my marketing manager probably will not like that answer. The slightly longer answer is between two weeks and six months.
Now the really long answer.
A search engine is a web site that has a database of other web sites. This database is created by programs called bots or spiders that crawl your web site. Directories are similar to search engines but a human being actually decides whether you get listed and in what category.
Your web designer will know what things they are supposed to do and what things they are not supposed to do. Things that will hurt your ranking include frames, inline frames, dhtml, appended url's, missing alt tags on images, missing title tags on links, broken links, non flat page hierarchies, excessive graphics, etc.. The things they are supposed to do include good titles, meta descriptions, meta keywords, content that includes keywords, h1 headers that include keywords, properly formed xhtml, valid xhtml, using text instead of graphics, including keywords in link text, etc. Sometimes the excessive use of a good thing can be looked upon by the search engine as a bad thing.
We try to do the right stuff and not do the wrong stuff. Sometimes it is hard to demarcate the best practices.
Some tactics might help with your indexing but make your site more difficult to use. In general I would aim toward having a helful, informative and easy to use web site.
There are three major Search Engines i.e. Google, Yahoo, MSN. Your web designer will submit your site to the big three and to DMOZ which is a large directory of web sites.
Once that is done, then it is really up to the powers that be to list your site. Other search engines will list your site based on the data from the big three.
Based on a quick search it seems that the average is 4 weeks to 2 months. You can check it out yourself. Go to a search engine and type in ' How long does it take to get listed on Search Engines.'