Twitter’s big mobile week continues as the company just announced Twitter for Nokia.

In an announcement on the Official Twitter Blog, product manager Brian Frank writes, “Nokia, the most widely used mobile platform in the world, now offers a fast, native Twitter experience for Series 40 feature phones. Beginning today, millions of people who use Nokia Series 40 devices can download Twitter for Nokia in the Nokia Store.”

“If you have a Nokia S40 device, you can sign up for Twitter directly from your phone, read Tweets from all of the accounts you follow, connect with others, and more,” adds Frank. “Download Twitter for Nokia now in the Nokia Store to discover one of the richest experiences available on your device.”

Earlier this week, Twitter revealed some new updates to its iOS and Android apps, equipping them with more features reminiscent of the desktop version of Twitter.

After that, an announcement came that Twitter and MediaTex have partnered to integrate Twitter into MediaTek’s mobile platform solutions, and get more feature phone users tweeting.

Yesterday, Twitter also posted to its blog to talks about all the improvements it has made to the mobil.twitter.com site, mentioning that JavaScript support and widescreen enhancements are on the way.