SIP is promising for VoIP signaling to support personal mobility. This paper first introduces and compares single registration (SR) and multiple registration (MR) for personal mobility. The SR scheme is weak in support of personal mobility without user's assistance. In contrast, the MR scheme supports personal mobility inherently by using sequential search or pure parallel search. However, sequential search may suffer from long delay for call setup, while pure parallel search consumes network resource. In this paper, we propose pipelined search for multiple registration. Both simulation and analytic results show that the proposed scheme compromises the two schemes in terms of delay and consuming network resource.