21 Sep 11 3:32 am
It depends on the frequency that google crawls the page you place the backlink on. There are some which Google will find within a day and others that can take a couple weeks or more.
Here is how you can test if Google has found a link of yours. Go to the page where the link appears, check if that link is there or has not been removed. Then copy the URL and type into Google:
And look at the cache. Does your link appear in it? If so, then Google has found your link and "knows" about it.
I hope this helps a bit!