six days a week can be done, but requires a delicate balance, lots of sleep guaranteed every night, very specific eating habits and good supplementation.
For a beginner, you're going to grow on just about any resistance program you choose to do, but some are going to give you better results than others. You need muscle everywhere, there is no real need yet to focus on just your arms for an entire workout - you're going to pack the most mass on them with heavy compound movements like the bench press, dips, chin-ups and rows, ESPECIALLY as a beginner.
Furthermore - as striking said - train your legs! Squats, deadlifts and cleans and presses are the BEST mass building movements out there and all work your legs tremendously.
Start with 3 or 4days a week, either total body routines or at most an upper/lower body split. Your split is unbalanced: you have to realize that you are training your arms 3 days in a row with what you are doing now. THEY NEED REST TO GROW!
Read up here on AM, there's plenty of good training ideas around. don't read fitness mags, their info is not pertinent to ANY beginning lifter.
If you want a specific program, check out Starting Strength by Mark Rippetoe, or there is an actual Westside training routine posted on here somewhere, just search for it.
Also, RenegadeRows threads on bulking have great training tips for gaining size.
One last thing - situps on the swiss ball are a real waste of time unless used post-exhaustion. Go with hanging leg-lifts, hanging pikes, reverse crunches, cable-crunches and, most important for good ab development, heavy standing movements like squats and deadlifts.
