On both iOS and Mac apps, you can import contacts into the app with vCard or vcf files. If you have an Excel or CSV file, the best way to convert it into vCard format is Gmail contacts. You can use these instructions to import a list of contacts in Excel into a Gmail account (you could create a new account just for this purpose if you don't want to use your personal Gmail account): http://support.google.com/mail/bin/answer.py?hl=en&answer=14024&topic=1669027&ctx=topic
Once you've imported, you can export all the data to a vcard format: http://support.google.com/mail/bin/answer.py?hl=en&answer=24911&topic=1669027&ctx=topic
Once you have the vCard file ready, you're set! From the main Contacts list page in CJournal, press the + button and select "Import vCard" and follow the instructions there.