tortilla: go to :
http://babymed.com/tools/pregnancy/hcg/
Plus in your HCG numbers and it will show them in comparison to the norm.
My first beta was 125 9dp5dt and my second was 317 11dp5dt. They both measured above the high end of normal for a singleton, but low for twins. The nurse said it can really go either way.
Beta's are really hard to judge. Anything over 5 is a maybe and anything over 25 is usually definitive.
However, everyone is different- I ran incredible high with my daughter and some theories suggest girls start off with a higher HCG level. Some women have a 30 something for a really healthy pregnancy and some women have 300 for the same

All your HCG can really tell you is if you are in fact pregnant, and if that pregnancy is progressing.
Here is a chart that I found at
http://www.bobrow.net/kimberly/birth/hcglevels.html. You'll see how vastly different HCG levels can be.
from conception from LMP (mIU/ML or IU/L)
7 days 3 weeks 0 to 5
14 days 28 days 3 to 426
21 days 35 days 18 to 7,340
28 days 42 days 1080 to 56,500
35 - 42 days 49 - 56 days 7,650 to 229,000
43 - 64 days 57 - 78 days 25,700 to 288,000
57 - 78 days 79 - 100 days 13,300 to 253,000
17 - 24 weeks 2nd trimester 4060 to 65,400
25 wks to term 3rd trimester 3640 to 117,000
After several days postpartum nonpregnant levels (<5)"