字符串有关问题

字符串问题
从文本文件中读入一个字符串，如：
148915000516   7654650005   577   0009484
想要判断字符串“000”出现的位置，并将“000”和其后面三个字符赋值到数组中去
即如下结果：
000516
0005   5
000948
用InStr函数时只能读第一次出来时的位置，怎么写代码比较好呢，请大家帮帮忙。

------解决方案--------------------
Private Sub Command1_Click()
Dim s As String
s = "148915000516 7654650005 577 0009484 "
Dim a() As String
a = Split(s, "000 ")
Dim b() As String
Dim i As Long, j As Long
For i = 1 To UBound(a)
If Len(a(i)) > = 3 Then
ReDim Preserve b(j)
b(j) = "000 " + Left(a(i), 3)
Debug.Print "b( " + CStr(j) + ")= " + CStr(b(j))
j = j + 1
End If
Next

End Sub

------解决方案--------------------
Private Sub Form_Load()
Dim ss() As String
s = "148915000516 7654650005 577 0009484 "
i = 1
Do
pos = InStr(i, s, "000 ")
If pos > 0 Then
ReDim Preserve ss(j)
ss(j) = Mid(s, pos, 6)
j = j + 1
End If
i = pos + 6
Loop While pos > 0
End Sub