xp_ReadErrorLog - Get records from the SQL Server log

xp_ReadErrorLog [number of the log file], [SQL error logs/Agent logs], [search string 1], [search string 2]

• Parameter 1 (int), is the number of the log file you want to read. The default value is 0 for the current log. 
• Parameter 2 (int), value of 1 reads SQL error logs, value of 2 reads SQL Server Agent logs. The default value is 1.
• Parameters 3 and 4 (varchar (255)), are search strings for the log entry. The default value is NULL.

Note for parameter 1: To get the list of archive files, use xp_enumerrorlogs:

http://copypastenet.blogspot.com/2011/08/exec-xpenumerrorlogs-list-of-archive.html