How to transfer songs to iPhone?

but I have a Iphone that's 3G, but all I wanted to do was get the tunes off my Itunes library and download that to my phone!
I've got thousands of songs on my itunes, so I don't need to buy anything from the Iturnes store.
when I connect my iPhone to my computer to charge it up, it automatically downloads any photos I've taken to my Iphoto, not that I really wanted to do that, but it does it anyway.
However, it won't let me transfer files from the Itunes library to my Iphone.
Someone suggested I needed to update my Itunes app on my computer, but I don't think it's that old....

Please give me some advice as how to get these tunes off Itunes and transfer to the Iphone.
Also, isn't there a website somewhere that tells you much of how to work an Iphone? I would think so....
TIA
LTMU

Note: Moved post to it's own thread. Please do not hijack someone else's thread with an unrelated issue.

You can use Home Sharing on iTunes; you'll need to setup an iTunes account if you don't already have one. You can also use Dropbox.