An in-text citation should lead your reader to the corresponding entry in the reference list. Therefore cite websites in text as you would any other source.  Use the first item that appears in the References/Work Cited list that corresponds to the citation (e.g. author name, article name, website name, film name)

For APA style that means use the author and date if known. If the author is unknown, use the title and the date (for long titles just use the first few words).  For sources with no date use n.d. (for no date) in place of the year: (Smith, n.d.)

Example in-text citation for website with no author:
The term "Nittany Lion" was coined by Penn State football player Joe Mason in 1904 (All things Nittany, 2006).

Corresponding entry in your reference list:
All things Nittany. (2006). Retrieved from http://www.psu.edu/ur/about/nittanymascot.html

For MLA style that means use the author or title if there is no author. Do not give paragraph numbers or page numbers.

Example in-text citation for website with no author:
The term "Nittany Lion" was coined by Penn State football player Joe Mason in 1904 (All things Nittany).

Corresponding entry in your reference list (note: URL is not required but is allowed):
All things Nittany. The Pennsylvania State University. 2006. Web. 12 July 2011.  Retrieved from http://www.psu.edu/ur/about/nittanymascot.html