Can I connect a macbook pro and an ibook g4 via ethernet with ibook in target disc mode?

Question

Well, that's the question, really. I just bought a refurb macbook pro as an upgrade for my sister's elderly ibook - which has been a great computer, but which can't run any system newer than Tiger, and which has an extremely crowded hard drive. We began setting up the new computer last night, and got to where we were instructed to use migration assitant to transfer files from the old machine. This is where things fell apart.
1. Although both machines were on my sister's wireless network, the macbook pro did not see the ibook.
2. When we tried to connect the machines via firewire, we had a new problem - our particular macbook pro does not have a firewire 400 port. Same problem when we thought of connecting my sister's extermal verbatim drive. The macbook pro recognized the drive when we connected via USB, but, after asking if we wanted to use Verbatim for Time Machine, it didn't seem to see it when we answered "Not now".
I have ordered an adapter for our firewire cable, but, in the meantime, I have an ethernet cable at home which I used to transfer data from my older iMac G3 to an eMac. Can I use this cable while putting my sister's ibook into target disc mode, or must I wait for the connector? It is VERY frustrating having such a hard time moving information from one Mac to another. I've been a Mac fan (and evangelist) for years because Macs are generally easy and reliable. But now we're stuck.
I've been reading the boards and understand that target disc mode is the way to go, since we can't use migration assitant to move files between an Intel machine and a PPC. The new macbook pro is running Lion, while the old iBook is running Tiger 10.4.11. Neither of us has any experience with Lion, though we've both used Macs for many years.
TIA!

Answer 1

Thanks, Niel! As it turned out, I had a LaCie rugged drive at my place which had both Firewire 400 and Firewire 800 connections and cables. So I hooked it up to the old iBook, pulled my sister's stuff onto it as instructed in the ppc to intel thread, and then hooked it up to the Macbook Pro. Problem solved! - almost. We did have two issues:
1. My sister has a lot of music - more than 12 gigs were on the iBook's hard drive, but only about 6 made it onto the Macbook Pro. Why is that? I also got a message, when I was trying to move the music folder from the old library onto the new one, that OS X needed this folder and it couldn't be modified. Again, why is that? How, then, do you move files from a PPC to a machine running Lion? Again, a lot of her music files did make it over, but not all of them.
2. All her photos did seem to come over - in duplicate, maybe even in triplicate. That is so annoying! The same thing happened to me when I was migrating between my old eMac G4 and my iMac G5. Why on earth does iPhoto do this, and how can we make it stop?!
But we did manage to get a lot of her stuff onto the new machine. When we get the adapter, she'll be able to add the files that are on the Verbatim drive. You've been very helpful!