The alignment files which were used as part of the pilot project are found under ftp://ftp.1000genomes.ebi.ac.uk/vol1/ftp/pilot_data/data. These are all aligned to NCBI36.
There are also GRCh37 alignments available for both the high coverage individuals (ftp://ftp.1000genomes.ebi.ac.uk/vol1/ftp/technical/pilot2_high_cov_GRCh37_bams/) and the exon targetted individuals (ftp://ftp.1000genomes.ebi.ac.uk/vol1/ftp/technical/pilot3_exon_targetted_GRCh37_bams/)
Please be aware much of the sequence data these alignments are based on is very short read data (36bp) and was generated a long time ago (~2008) so may not reflect current sequencing data.
A more modern data set for the CEU trio is available from Illumina on their Platinum Genomes page.