The European Paediatric Clinical Trials Register is at http://www.dec-net.org/, and there is an article about it in Archives of Diseases in Childhood for June. This register is the only one exclusively for paediatric trials and involves the UK, Italy, France and Spain. The register contains information for parents and for professionals.
Meanwhile the International Committee of Medical Journal Editors have issued a statement about registration of clinical trials. They have already said that they will require trials to be registered if they are to be included in articles submitted for publication. Their statement, "Is this clinical trial fully registered?" is available via the NEJM website (free) at http://content.nejm.org/cgi/content/abstract/NEJMe058127 and also in the Lancet of May 28th-June 3rd. The statement answers questions about this requirement for trials to be registered and discusses the data set needed for registration, among other issues.