Many patterns are born out of necessity - and this falls in that category too. My daughter and her friends decided to add jogging to their exercise schedule, and wanted to be able to use their phones for their individual music choice (and also stay in touch, which is so essential for everyone these days!). This is my second design for a mobile phone puch - for use during exercise.
Inspired by the tennis wrist/arm band, this pouch is attached onto a band (so hands-free when exercising / jogging and yet easy to slip on and off).

The pattern is a simple one, but uses post stitches in part.

While this pouch has been designed for the HTC Desire series phone(s) and I-phone (5 and 5S) series, it is simple enough to be altered to fit any phone. It has also been tested and fits the Motorola Droid Razr M phone.

This pattern has been tested using :
a) 4 ply yarn , Oswal Mills ; 15 gms / 65 yds ; 4 mm crochet hook ;

b) Lion Brand Cotton Ease, 93 yds, G hook
Comments : Quick pattern. Took 2 hrs. Followed your pouch as it made a snug fit for my phone which is a good thing.
Skill level by tester : Easy

c) #3 weight of discontinued acrylic ; 1/2 oz = 57 yds ; 4 mm (G) crochet hook ;
Comments : Took about 2-3 hrs, Instructions were clear, photos/illustrations were helpful, all techniques explained well.
Skill level by tester : Advanced due to the post sts used.

d) Caron Simply Soft ; 46 gms ; 4.5 mm crochet hook ;
Comments : Very clear instructions, illustrations and photos ; all techniques well explained ; took about 3-5 hrs to complete the project. Cute pattern. Fits my Motorola Droid Razr M
Skill level by tester : Easy