Either implement an Exchange 2000 server running IM within your Exchange
2003 environment, or implement LCS as you've noted. Of course, ultimately
support for Exchange 2000 will disappear, so the LCS route is probably best.

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Neil Hobson
Exchange MVP
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> does exchange 2003 allows integration with IM as exchange
> 2000 does? if not, is the only way to get this sort of
> communication on exchange 2003 to implement Live
> Communications server 2003? any help would be greatly
> appreciated!