As it tries to expand the ways people can post videos online, YouTube launched on Wednesday a service that allows users to upload homemade clips <A HREF="http://news.zdnet.com/2100-9595_22-6070527.html?tag=zdnn.alert">via their mobile phones or PDAs.</A> A growing number of handheld devices are capable of recording video. The new service will likely produce greater numbers of spontaneous and candid clips.