I am not sure if you mean the Docs to Go is in Spanish or your device is in Spanish.
Assuming the device is, take a look at this Palm article to see if you can change the language of your device. Some support it, some don't:
http://kb.palm.com/SRVS/CGI-BIN/WEBC...ortKB,CASE=574
I am not sure about a free download of English Docs to Go though. Docs to Go is usually included on the CD that comes with the device. You can get a trial version here:
http://www.dataviz.com/downloads/demo/index.html
Keep in mind that the language needs to be the same for the OS as well as the software including your Palm Desktop.
SteveTaz