Something like:
SELECT * FROM sys.functions
for SQLServer2005 it is:
SELECT * FROM sys.objects WHERE type in ('TF','FN','IF')
This will give you the names and the definitions :
SELECT SPECIFIC_NAME, ROUTINE_DEFINITION FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_TYPE = 'FUNCTION'
Something like this will give you all the details of the udfs you've created.
SELECT * FROM sysobjects WHERE (type = 'TF' OR type = 'FN' OR type = 'IF') AND objectproperty(id, 'IsMSShipped') = 0
Get rid of the second condition if you want everything.
for SQLServer2005 it is: