The easiest way would be to get DB2 Connect (requires a license which is not free unless you get Try and Buy), and the export the data in del format (and name it data.csv). Not sure if you can connect directly to the database from Excel using ODBC. If you have problems, make sure you specify the code page on the export command. You will also have to do a remote bind (one time) from the DB2 client to the z/OS for DB2 client utilities if no one has previously done it for the client version/fixpack you are using.
There may be a way to extract data in comma delimited display format on z/OS and then file transfer the dataset to your PC (you will need some kind of file transfer program that will convert from EBCDIC to ASCII such as usually included with 3270 terminal emulators).
M. A. Feldman
IBM Certified DBA on DB2 for Linux, UNIX, and Windows
IBM Certified DBA on DB2 for z/OS and OS/390