LHDN has now opened access for e-filing 2008 at their website:- E-Filing
Do take note that closing date for e-filing shall be 30th April 2009.
for those who have already used e-filing since submission year 2005, you may use the same login (I/C number) and password as the digital certificate is still valid.
For those who are still new to e-filing, you will have to go to any LHDN office and obtained your "no. pin" to enable access into the e-filing system. At their website, it also mentions that no. pin is also available by letter, fax or e-mail with the relevant details provided. Check it out at the e-filing website.
The time i collected my no. pin back then, i just showed my I/C card and the officer gave me the no. pin slip, as easy as that.
Once you have the no. pin, just "login first time" and you'll be on your way. If you need some guide, it's easily available at LHDN website: here
ADD. INFO: E-Filing is using "Roaming PKI Certificate" which means you can login and access into e-filing page from just any computer and not necessarily the computer which you registered initially. As this is very convenient, however be careful with which computer you use, if your login details are taken (for instance by means of a keylogger), anybody can simply login into your account and abuse it.