How do I check that whether the tivo got pal tuner?
It's got a PAL tuner - and one of my installs at that. Just looked at your picture gallery and saw it.

Tivo comes with the network card, so it will connect to the switch, which is connected to the my internet gateway.
OK that's easy then. Your switch (router maybe?) should be able to dish out DHCP assigned IP addresses which will make your network connection a snap.

Now, I tried to directly swapped VCR with tivo - taking the connection from the VCR and then connected to tivo. I can watch all the channel from optus STB, DVD is ok.
So if I understand you correctly you have taken the RF antenna cables out of your VCR and plugged them into the antenna input and output connectors of the TiVo, yes? If so then this is fine. Most people use the A/V video and audio output connectors from the TiVo to the TV (like you have for your DVD player) but if you want to do it via a UHF antenna signal then that is your decision.

But, I cannot get my tivo working. I can see the green light and whenever I click on tivo remote, it changes to orange briefly, but nothing else. I changed the channel on tv, changed the video mode1 and 2, still the same.
Well, if you have simply connected the TiVo for where the VCR was in the antenna cable chain I'm not surprised you are not seeing anything. As the white sticker says on the back of the TiVo "UHF 60" and by default the software on the TiVo outputs the RF signal from the TiVo on just that: UHF channel 60. You will have to tune your TV into this channel to see anything.

What should I see when everything is connected ok?
The greenish coloured "TiVo Central" screen once it has finished booting up. A smallish picture of this is in the picture on the front page of my website where you see the text "WELCOME" (link is in my signature).

Also, how can I get into maintainence mode?
With a freshly installed hard disk? It will automatically boot into Guided Setup.

With an already installed and already set up hard disk (I'm tipping this is what you will have given you have purchased it already working from eBay)? Ahhh, THAT is where you are going to need to follow a procedure which assumes you already have your network connected AND you know how to obtain your IP address from the TiVo:

1. Gain access to TiVoWEB by pointing your web browser at the IP address of the TiVo

2. Go to the PAL/NTSC tab

3. From within this menu pick "Set PAL Guided Setup Mode"

4. Reboot TiVo

5. When you get the main menu appear on the TiVo, go into "Messages And Setup" and then "System Reset" then "Repeat Guided Setup"

Then follow the instuctions here:
http://minnie.tuhs.org/twiki/bin/vie.../GuidedSetup30

*DO NOT* try and skip directly to step 5. It does not work while your TiVo is in normal operating mode, only in "Maintenance Mode". You can try, but you will keep getting kicked back to the main menu.

Cheers
Darren