The developers behind Post Mobile, which has been built in partnership with Bluestar Mobile and Nokia, hope it will work on the majority of mobile phones.
Trinity Mirror announced in July its plans to launch mobile sites across its titles. The Mirror site launched last week.
Mobile sites will next be introduced to its titles in Huddersfield, Liverpool, Newcastle and Wales.
The Post reports that versions of the website content designed for a smaller screen are available, alongside the option to customise the site's homepage to select different content, send stories to friends, or post comments on specific Post Mobile forums.
In an article for Thursday's edition of the paper, Marc Reeves, editor of the Birmingham Post, said: "Post Mobile is a central part of the changes we have introduced this week. The service makes the Post even more accessible for more readers throughout the day."
Joanna Geary, development editor at the Birmingham Post, said Ofcom has reported that over a third of Birmingham residents check the internet on their mobiles.
"It is an absolute must for Birmingham Post to be a part of this new platform and we hope with the launch of Post Mobile we have done that."
Geary said that over the next few months 'they hope to increase the content on the site and provide more ways to personalise the homepage'.