How can I record interviews (phone and otherwise) to post online?

I would like to record interviews with researchers to share on an internet radio site. I will sometimes call them via phone or meet with them and record them that way. I would have to convert them to MP3’s. What would I need to get——to record interviews on the phone (type of phone, mike, recording equipment) and also in person. I don’t like listening to internet interviews where the guest is garbled and unintelligible…that’s a concern for me. There must be a good way to record in good quality?

Any ideas/leads would be greatly appreciated. And (as I’ve remarked before, I am not that tech savvy——so please, be kind. LOL) Thanks everyone!