Some people say two thousand for 2000. But we can also say twenty hundred (just as we say "nineteen hundred" for 1900).
And for the following years:
- 2001 two thousand (and) one or twenty-o-one
2002 two thousand (and) two or twenty-o-two
2010 two thousand (and) ten or twenty-ten
2025 two thousand (and) twenty-five or twenty-twenty-five