Mobile Lowdown: 6-21-11: PlayBook Email; Samsung/Apple; Seesmic/RIM; HTC

A look at some of the big stories in mobile today:

PlayBook: Wondering why the PlayBook tablet lacks native email support for BlackBerry users? One person claims it’s because of the security that was built into the BlackBerry Enterprise Server. (via BusinessInsider)

Samsung/Apple: Are the two handset makers trying to resolve their respective patent and trademark lawsuits out of court? Apple (NSDQ: AAPL) says yes; Samsung says no. (via V3)

BlackBerry: End of the social media road for RIM (NSDQ: RIMM) — on one platform at least? Seesmic says it will stop supporting RIM’s BlackBerry OS to focus on its iOS, Android and Windows Phone clients, effective June 30. Meanwhile, reports of RIM putting pressure on operators to sell their “half-baked” devices. (via BGR)

LightSquared: One possible solution for the new LTE network to avoid GPS interference? Use lower spectrum bands. (via FierceWireless)

Zune HD: Looks like Microsoft (NSDQ: MSFT) is preparing to put some of its own Zune HD apps on Windows Phone. (via Windows Phone Secrets)

HTC suit: The patent holder IPCom is suing HTC in the UK over patent infringement in certain 3G devices. IPCom sued Nokia (NYSE: NOK) for the same infringement and that claim was upheld by the court. (via Bloomberg)