There are confirmed reports in the Google Places Help forums that the Google Places post to your place page feature does not work.
In short, you can go to your place page in Google, click on impressions, and then at the top right of the page, it gives you a box to post something to your place page. If you try it, it might appear to work, but your place page won't show the post.
Google's Ashley said this is a known issue:
This is actually a known issue and we are working towards a solution. Hopefully it will be back up and running soon!
There is not ETA for a fix but I am honestly not sure how often this feature is used.
Forum discussion at Google Places Help.

Comments:
Chris Lang
11/25/2011 01:21 pm
Do you think Barry, that this could the start of Google+ replacing this function?
Barry Schwartz
11/25/2011 01:22 pm
kinda, maybe. this is a bit different
SEO Catalysts
11/25/2011 03:17 pm
I think every local business promoter know this feature and all of them are using but the question is if Google do not want to display this then why they are putting such kind of thing??? ---- Search Engine Optimization
Ronnie Kirchner
11/26/2011 08:52 am
You would of thought it would be fixed by now...whats gives