In browsing the blogosphere some while back I spotted product review page by a blogger with a section of reviews of things they had tried / bought and found that worked (blog - 'I'd Rather Be Eating'; page "what am i a camel ifitness review". I read with interest their review of a running belt that they had worn for the first time in a marathon and had absolutely no issues with. As someone who suffers chaffing really badly (I wear a compression vest or t-shirt to avoid horrible joggers nipple!), I had always been shy of wearing any kind of belt or bag whilst running.
Inspired by the review and then by the ifitness website I purchased one and tried it out on a long weekend run. Wow, no rub even having loaded my iPhone, keys and a gel pack onto it.
That was a couple of months ago now and I have enjoyed using it on near enough every run. It is great to have a phone with me, and I have been trying out the gel packs in earnest now (with a possible future marathon in mind). It is completely comfortable, I forget that I am running with it and has thus far stood the test of British weather / profuse sweat. If you want to try a belt I can recommend you have a look around their website.