Lately I have been using SharePoint Designer alot for modifying SharePoint pages. This is very largely based around XSL, and today I had the task of comparing a date to today's date. This meant of course that I would need today's date. It was after a little searching I found this incredible resource here, which details a whole stack of hidden functions in the ddwrt space that SharePoint has access to when displaying pages.  

From this I quickly found out that I could easily use the following to display today's date: 

 < xsl:value-of select="ddwrt:Today()">

I quickly also learnt that to display a date variable in the different formats you simply use the following function:
FormatDate(string szDate, long lcid, long formatFlag) where I am using FormatDate(@Today, 1033, @No);  

1  : 5/9/2007
3  : Wednesday, May 09, 2007
4  : 9:06 AM
5  : 5/9/2007 9:06 AM
7  : Wednesday, May 09, 2007 9:06 AM
12: 9:06:12 AM
13: 5/9/2007 9:06:12 AM
15: Wednesday, May 09, 2007 9:06:12 AM

This didn't help for doing a date compare. Lucky there was one other function to try out -
FormatDateTime(string szDate, long lcid, string szFormat);

So by using it:   

 < xsl:value-of select="ddwrt:FormatDateTime(string(ddwrt:Today()), 1033,'yyyyMMdd')" > < /xsl:value-of > 

I was able to get the date 20070509 (for May 9, 2007 for example) which meant I was almost there for doing my date compare.
Finally then, to check for a date that is expiring today, or has expired I was then able to use the simple XSL query: 

 < xsl:if test="ddwrt:FormatDateTime(string(ddwrt:Today()), 1033, 'yyyyMMdd') >= ddwrt:FormatDateTime(string(@Milestone_x0020_Date), 1033, 'yyyyMMdd')" >

Expired!! < /xsl:if >