Just trying to save money

I have a Comrex Bluebox and the station I host a program for has a BricLink running Opus. The free SIP application LinPhone works great on my iPhone. Is there an easy adapter to hook up the three channel cell output of the BlueBox to the four channel input of my iPhone. It would be nice to have adjustable mic and headphones (sorry if I posted this before)

First, you'll need a XLR/F to T-R-R-S mini-phone plug adapter. Cable Jive has one http://www.cablejive.com/products/ProJive-XLR.html. The BlueBox line out is way too hot for the mic level input of the iPhone, so you'll also need an in-line attenuator http://hosatech.com/product/att-448/.

Thanks everyone for the advice, I found that iRig had a $20 microphone that allows you to talk and listen (built in headphone jack) that isn't terrible. This morning during my show I used it and as an emergency backup to a POTS codec or even an IP codec isn't bad. If you listen about 18 minutes in to this podcast I take a break leave the studio walk around and return to the studio. There is some echo and feedback from studio monitor speakers http://johnfpaul.podomatic.com/entry/2015-04-04T09_17_58-07_00
Total investment free Linphone app and a $20 cell phone mic from iRig its not a Comrex Access but in a pinch could get you out of trouble on a remote.