A dedicated XML standard for datasynchronisation of PDAs is SyncML(http://www.syncml.org/).
freedesktop.org(http://freedesktop.org/) is a free software project to work on interoperability and shared technology for desktop environments for the X Window System. The most famous X desktops are GNOME and KDE but any developers working on Linux/UNIX GUI technology are welcome to participate.
vCards are an existing and widely-used standard for personal user information storage, somewhat like a business card. For Linux connectivity and tools see here.
The Mobile Industry Processor Interface - MIPI(http://www.mipi.org) Alliance is a collaboration of mobile industry leaders with the objective to define and promote open standards for interfaces to mobile application processors. Through these open standards, the MIPI Alliance intends to speed deployment of new services to mobile users by establishing specifications for standard hardware and software interfaces to mobile application processors and encouraging the adoption of those standards throughout the industry value chain. Founded by ARM, Nokia, STMicroelectronics and Texas-Instruments - TI as an evolution of the OMAPI(SM) Standard, the MIPI Alliance is intended to complement existing standards bodies such as the Open Mobile Alliance and 3GPP, with a focus on microprocessors, peripherals and software interfaces.
The 3rd Generation Partnership Project - 3GPP(http://www.3gpp.org/) is a collaboration agreement that was established in December 1998. The collaboration agreement brings together a number of telecommunications standards bodies which are currently ARIB, CCSA, ETSI, T1, TTA, and TTC. The original scope of 3GPP was to produce globally applicable Technical Specifications and Technical Reports for a 3rd Generation Mobile System based on evolved GSM core networks and the radio access technologies that they support (i.e., Universal Terrestrial Radio Access (UTRA) both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes). The scope was subsequently amended to include the maintenance and development of the Global System for Mobile communication (GSM) Technical Specifications and Technical Reports including evolved radio access technologies (e.g. General Packet Radio Service (GPRS) and Enhanced Data rates for GSM Evolution (EDGE)).
The Open Mobile Alliance - OMA(http://www.openmobilealliance.org/) aims to grow the market for the entire mobile industry by enabling subscribers to use interoperable mobile services across markets, operators and mobile terminals. This is achieved by defining an open standards based framework to permit applications and services to be built, deployed and managed efficiently and reliably in a multi-vendor environment.
"W3C has a particular interest in Mobile Access technology. The Consortium is working towards making information on the World Wide Web accessible to mobile devices, many of which are characterized by small screens, limited keyboard, low bandwidth connection, small memory and so on." See their W3C Device Independence Activity(http://www.w3.org/2001/di/) (Access to a Unified Web from Any Device in Any Context by Anyone) and other documents.
The Multimodal Interaction Activity - MMI(http://www.w3.org/2002/mmi/) is extending the Web user interface to allow multiple modes of interaction, offering users the choice of using their voice, or an input device such as a key pad, keyboard, mouse, stylus or other input device. For output, users will be able to listen to spoken prompts and audio, and to view information on graphical displays. The Working Group is developing markup specifications for synchronization across multiple modalities and devices with a wide range of capabilities.
The Linux Phone Standards Forum (LiPS)(http://www.lipsforum.org) is a consortium founded by a group of telephony operators, device manufacturers, silicon and software vendors who have a strategic focus on Linux(tm) telephony.
These are the standards already known from laptops: APM, ACPI, PCMCIA-CS, VESA, ..