Study to Evaluate Safety and Immunogenicity of GSK Biologicals' Pandemic Influenza (H1N1) Candidate Vaccine in Children

Inclusion Criteria: All subjects must satisfy ALL the following criteria at study entry: * Subjects who the investigator believes that their parent(s)/Legally Acceptable Representative(s) (LARs) can and will comply with the requirements of the protocol * Children, male or female, aged between 8 and 12 weeks at the time of first study vaccination. * Written informed consent obtained from the parent(s)/LAR(s) of the subject. * Healthy children, as established by medical history and clinical examination when entering the study. * Parent/LAR with access to a consistent means of telephone contact, land line or mobile, but NOT a pay phone or other multiple-user device. * Born after a gestation period of \>= 36 to \<= 42 weeks. Exclusion Criteria: The following criteria should be checked at the time of study entry. If ANY exclusion criterion applies, the subject must not be included in the study: * Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine within 30 days preceding the first dose of the study vaccine or planned use during the study period. * Acute disease at the time of enrolment. * Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination (no laboratory testing required). * History of any neurological disorders or seizures. * A family history of congenital or hereditary immunodeficiency. * Receipt of systemic glucocorticoids within one month of study enrolment, or any other cytotoxic or immunosuppressive drug since birth. * Administration of any vaccines within two weeks before study enrolment. * Administration of immunoglobulins and/or any blood products since birth or planned administration during the study. * Previous administration of any H1N1 vaccine, of any seasonal influenza vaccine. * Previous vaccination against diphtheria, tetanus, pertussis, poliomyelitis, Haemophilus influenzae type b, and/or Streptococcus pneumoniae with the exception of vaccines where the first dose can be given within the first two weeks of life according to the national recommendations. * History of intercurrent diphtheria, tetanus, pertussis, poliomyelitis, Haemophilus influenzae type b disease. * Major congenital defects or serious chronic illness. * Child in care. * Any known or suspected allergy to any constituent of the influenza, DTPa-IPV/Hib and pneumococcal study vaccines; a history of anaphylactic-type reaction to consumption of eggs; or a history of severe adverse reaction to a previous influenza, DTPa-IPV/Hib and pneumococcal vaccine.