Howdy,
Vit-All is a gutload

. Feed it to your feeder insects about a day before you feed them to your chameleon.
Sorry Dave - my bad. I just skimmed through the blurb about the product and assumed Vit-All was Sticky Tongue's version of Herptivite, but you're absolutely right - it's a gutload.
So to Tryme: I don't think Vit-All (even used as a gutload) would be an adequate replacement for Herptivite. The other candidates on that Livefoods site include Zoo-Med's Reptivite and the Medi-Vet Reptavite.
I can't find any information about the Medi-Vet product, so I can't vouch for what it contains, but these products often have both D3 and pre-formed vitamin A, which can be overdosed on - that's why the Herptivite one has always been recommended.
The Zoo-Med product contains calcium, and it has been reported that when calcium is combined with certain vitamins it may degrade them, so I've always tried to steer clear of such combos. Also, Zoo-Med's product comes in a version with D3, and a version without D3. Since you'll already be providing D3 along with your D3 calcium supplements, you should get the Reptivite without D3, but that website doesn't mention which one they're selling.
Ok what like once a month or something?
If you're referring to using the Vit-All as a
gutload, then you should
always be feeding it to your feeder insects for about 24hrs before you feed them off to your chams.
If you are referring to how often you should be using a multi-vitamin supplement (and we've established that Vit-All is not one), then you should use it once or twice a month, as suggested by Jannb's post and Brad's blog.
Sorry about the confusion caused regarding the Vit-All.