that doesn't make any sense.
how would knowing true heading help with an instrument approach in an emergency.. all the bearings on an instrument approach are magnetic, all headings given by atc are magnetic.
and also, I've never heard of an ipad or notebook with an ILS receiver (have seen handheld vhf's with VOR mode tho) -- maybe you mean GPS. Even so, those headings are magnetic also.
About 2 weeks ago, I saw a story on CNN, concerning a pilot flying what looked like a Beech single engine aircraft, who complete failure of electrical system and he was talking about an "ap" for his "Ipad, which he used to shoot the approach and land safely.
I am not sure, but I believe this is a photo of a Ipad or something, by which you can download instrument approach and navigational charts, On Jeppensen.com web site.
If you were, say, somewhere in California and had nothing but your magnetic compass to give your direction and you were getting radar vectors for landing, say a ASR approach to Burbank, and he told you to fly 090, what heading would you line your compass on to fly that heading?