new to xml

hi,
same old statement- "new to xml". i am planning to learn xml . and i have a few doubts.
books - i have many. not planning to buy anymore.
what are the various software i need before i write xml code?
how long does it take t get the feel of xml and become if not an expert atleast get comfortable ?
when can i decide that ok ! this is the time to think of getting certified ?

any suggestions are appreciated.
thank you.
sridevi

1.XML Bible is a good book to start with.
2. xmlspy is among the best tool for writing xml code and
verifying and validating it.
U can use simple notepad for writing the xml code and verify it
using ie5 or mozilla.
for validation xt is also a good tool.
try ibm sample question and see the score to find out where u stand before taking the exam.
sanjay