The Geo database contains an abundance of raw sequence tag files in fastq format some of which are generated by Solexa/Illumina NGS. Since Solexa/Illumina decided to change their own standard from version 1.3, both of which are not compatible to the sanger format, there exist currently 3 separate fastq definitions. I was wondering if there is any (easy) way to determine, which version was actually used to generate the fastq file (in particular for Solexa/Illumina since the platform is usually stated). Thats something you have to provide to nearly any aligner so that piece of information seems rather valuable.
You should check, but I believe that the NCBI SRA archive, which actually hosts the FASTQ (not NCBI GEO), is claiming to have converted the FASTQ files into sanger standard FASTQ. Once the data are there, the idea is that you needn't worry about the conversion as it is supposed to have been done.