how to update my ibook G4 with out itunes

Your question begs more questions before an answer...

What are you trying to upgrade, and why would you try to use iTunes

in a vintage G4 computer that cannot run an OS X later than 10.5.8

at best? (and only if it has a processor at least 867MHz or better)

With at least a 1.0GHz iBook G4 you could run Leopard 10.5.8, and

the system requires a retail DVD to install the 10.5, then go online

after installation, to get the Combo 10.5.8 update, by use of Software

Update within that first earlier system...

If the computer does not have at least the minimum processor, it would

not be able to see Leopard as a system, so Tiger 10.4.11 is the last...

http://www.apple.com/support/leopard/

iTunes does not upgrade or update much of anything in an obsolete &/

or vintage Mac OS X before the Intel-Mac era, and prior to OS X 10.6.8.

If your computer does not have an iTunes version at all, you can go to

Apple support downloads and look at older iTunes, and older safari,

and some other bits that are limited to their respective vintage OS X.

Usually the upgrade path utilizes DVD media or CD media, for software

& depending on what kind of software, then later get update-downloads.

To see if there may be anything not already installed in the system or

applications that could exist in the Apple support download servers,

you could see if the System's own Software Update, located in Apple

Menu in upper left side of the menu bar in Finder, can locate some.

If you perform a new install and did not save all the bits as downloaded

from when they were more current, some updates to original media that

formerly were online and available as download (step updates, not full

upgrades) you may eventually be unable to upgrade then update an older

OS X system; the remainder of the later or last fixes were in the update.

So, if you have an old G4 PowerPC Mac computer running, say Tiger 10.4.3

and thought to use some software intended to run in Tiger 10.4.11, then

you'd have to see if Software Update could find the 10.4.11 Combo update.

After updating the main system, other applications may also see a need to

be updated, if they were not already as far as they could go, in their vintage.

iPhoto, and other applications, such as they were, had updates to their main

application. So with iTunes, the last version that can work in a PPC G4/G5

non-intel would be in the last supported OS X, Leopard 10.5.8, and that

version number is iTunes 10.6.3; so you can't visit an App Store or Mac App

Store nor can you run Snow Leopard on a PowerPC architecture Mac.

With the intel-based Mac, and Snow Leopard, you can access the online

Stores to include recent Mac Apps, App Store, iTunes Store, etc. A light

version of early iTunes (see iTunes Player) can be seen, and their Radio

still plays free music channels. I have several older pre-Intel Macs...

The matter involves the vintage of the device, the system, and limits of the

old vintage/obsoleted configurations where both are interdependent.

Not sure if this helps, but more of a history lesson may be read if you look

into everymac.com and compare models, build years, and other specs...

If you need some feature or function not supported by vintage hardware or

vintage software, or a newer web browser, you have to look further. A fair

browser can be found in TenFourFox. I use it daily in a PPC G4 MINI 1.5GHz.

with Leopard 10.5.8. Plus others. To go further, look into an Intel-based Mac

such as MacBook2.1 & then buy the Snow Leopard retail DVD for about $20.

Hopefully this helps somewhat...

Good luck & happy computing! 🙂