After weeks of waiting, SimplyTweet 1.7 has finally been approved.
Improved Posterous support
Since adding support for Posterous in v1.5, SimplyTweet has been one of the only (and likely still the only) iPhone Twitter client which supports multiple photo uploads to a single Posterous post, like it should.
With 1.7, if you post photos to Posterous in a tweet, SimplyTweet will automatically convert hashtags to Posterous tags.
Other features
There are many other enhancements and fixes including being able to pick hashtags from the tweet you are replying to, showing different bubble colors in timelines to indicate whether a tweet is sent by you (any of your accounts, not just the currently logged in account) or mentions you (again, any of your accounts).
Retweetability Count Indicator
Also known as character count checker for the vain.
If you like people to retweet your tweet, you really ought to make sure your tweet is short enough so they can include your name and the RT text (e.g. RT @simplytweet I like both Coke and Pepsi). When drafting a tweet, the tweet character counter now turns red when you exceed the number of characters which allow others to retweet you without truncating your original tweet. This takes into account the length of your Twitter account name.
No more manual counting!