Without respect to you expression values (...because we don't know, how those expression values were calculated...) a good choice for your list of genes could be http://david.abcc.ncifcrf.gov/home.jsp or http://bioinfo.vanderbilt.edu/webgestalt/.
If you will use those sources, keep in mind your reference dataset! ...default reference set is the whole genome!
Furthermore, if you gene list is just a small list. Try http://biogps.org/#goto=welcome and add your pathway modules of interest (STRING, KEGG, etc).
I second my colleagues: Your question is not very clear.
As far as I understand your question, a good start would be to use the KEGG database or download flat files of interest on their FTP server: http://www.genome.jp/kegg/download/
Depending on your programming skills you can either write your own parser, or use available tools, like KeggArray if you are working with arrays.
Hope it helps
I developed a script that takes a directory with several gene list inside (Entrez Ids) and a universe set, a pvalue cutoff and an FDR cutoff and looks for enrichment in KEGG pathways, could be also GO ( I am using GOStats bioconductor package )
The script is just right here, if you find it useful please leave a comment