By 64 bit windows 2003/sql 2005, the solution is installed 32 bit ole db provider for jet(should already be installed by windows or SQL server), use a 32bit executible to call the 32 bit ole db driver for jet to load your data. You call the 32 bit executible in your T-SQL (e.g. xp_cmdshell) or in your job step (set command type to operating system).
E.g. 64 bit sql server also installs 32 bit DTSRun.exe. You can use it to run 32 bit SSIS package, which does the data import, in 64 bit machine.