[UW-GIS-L] Transformation of WGS84 to UTM?

[Kim Jhee]

Hi All,
Currently we are working on making a prototpye demo of GIS relative system. 
The demo should provide the capability of convertion between WGS84 and 
UTM.So we are working to transform WGS84 coordinate to UTM coordinate.We 
tryed the Gauss Krueger Projection. But the results we got is about >10m 
error in northing and <5m error in easting compared to the converter get 
from net: http://franson.com/coordtrans/index.asp?ref=google

My questions are:
1. Is there any comparation of the algorithm or formula to converting WGS84 
to UTM? Is there any data to show some different formulas and their 
relative error?
2. Could you recommand one formula/method to convert WGS84 to UTM and 
result in small error?

You also can points me to one reading list or net resources. 

I think this shouldn' be a new question for this list or may be too simple 
question for this list. Anyway, any feedbacks and recommendations are 
welcome and highly appreciated. Thanks a lot.

Best Regards,
Jhee