Both UserAlt and UserSmallCaps are derivatives of Source Sans Pro which, since 
modified, has had its name change.  The following changes have been made:

1) Subsetting.  Only English and Spanish are supported.

2) No open type (Open type renders poorly in Windows, even Windows 7); only
   true type .ttf files used.

3) Bold here is semi-bold with small caps.

4) Regular "Alt" uses different forms (included with Source Sans) for
   "g" and "l" to look a little more conservative.

4) Fonts rehinted with ttfautohint.

5) Tighter line spacing.

This is the font used for sans serif text in my resume.

The original Source Sans Pro is available here:

http://sourceforge.net/projects/sourcesans.adobe/files/

http://samiam.org/fonts/best-opensource/Source-Sans-Pro/