alternate to IF EXISTS ..UPDATE ELSE ..INSERT

Unlike 'xType' in sysObjects, you wont be able to find what exactly those values mean in syscolumns table as in the BOL it is written mentioned as 'For Internal purpose'. The sysstem table which stores this information is sysTypes

SELECT xtype, name FROM systypes
ORDER BY xType

and the results

XType Datatype
----------------
34 image
35 text
36 uniqueidentifier
48 tinyint
52 smallint
56 int
58 smalldatetime
59 real
60 money
61 datetime
62 float
98 sql_variant
99 ntext
104 bit
106 decimal
108 numeric
122 smallmoney
127 bigint
165 varbinary
167 varchar
173 binary
175 char
189 timestamp
231 nvarchar
231 sysname
239 nchar
241 xml