The paper discusses means to build multi-modal data services in existing GPRS infrastructures, and it puts the proposed simple solutions into the perspective of technological possibilities that will become available in public mobile communications networks over the next few years along the progression path from 2G/GSM systems, through GPRS, to 3G systems like UMTS, or equivalently to 802.11 networks. Three demonstrators are presented, which were developed by the authors in an application-oriented research project co-financed by telecommunications companies. The first two, push-to-talk address entry for a route-finder, and an open-microphone map-content navigator, simulate a UMTS or WLAN scenario. The third demonstrator implements a multi-modal map finder in a live public GPRS network using WAP-Push. Some indications on usability are given. The paper argues for the importance of open, standards-based architectures that will spur attractive multi-modal services for the short term, as the current economic difficulties in the telecommunications industry put support for long term research into more advanced forms of multi-modality in question.