SharePoint doesn't tell IIS about post webapp creation.

Be aware if you create an Alternate Access Mapping (AAM) for a web app in Central Administration, you still need to add the host header for the new address  into IIS   .

Should we use virtual SQL server for SharePoint?

RAM, CPU, or drive space all are restricted in Virtual enviornment
Everything in SharePoint is stored in SQL Server, if SQL Server is slow, SharePoint is slow.
This should be last option. Recommended in physical box. if you have to create a virtual sql server plese see following video http://technet.microsoft.com/en-us/sqlserver/gg429826.aspx

log of login attempts to sharepoint 2007?

I am still searching for it and couldnt find. one solution may be to create list and then update list through user control embedded in master page.

Minimum RAM or Hard Disk Space requirement

Moss2007 requires following minimum prerequisite for performance

https://technet.microsoft.com/en-us/library/cc262485(v=office.12).aspx

What is Code Access Security in SharePoint 2007

I've started to write a piece on What is Code Access Security in SharePoint 2007 and thought I'd put the draft up here to get some feedback -- especially since configuring security has taken prominent place. I'd really appreciate all of your feedback. Thanks! Hament

These days, you can't pick up a blog without reading about the need for the customizing SharePoint as per need of organization. Most of these are done via setting configuration and some time by custom programming too. We as programmer need to think carefully before tweaking the setting for WSS_Minimal and WSS_Medium trust levels. In exceptional cases a third configuration ‘Full’ can also be set. Let me warn you here that this may have serious implications and you may not be able to convince the security group to deploy it in production boxes.

Earlier the security were declared in the web.config file, but that doesn't seem to be the case any more. You will find two pointers to config file of folder localdrive:\program files\common files\microsoft shared\web server extensions\12. The classes are configured for code access level. For example you will find out that SqlClientPermission are not allowed in WSS_Minimal but is allowed in WSS_Medium trust.

Extending OCS

In OCS integration with sharepoint you can extend ocs via SDK
here
Two ways of extending the OCS are discussed here
here

STSDEV: Sharepoint Code generator

STSDEV is a proof-of-concept application that demonstrates a simple code generator for create SharePoint 2007 development projects targeting Visual Studio.
http://www.codeplex.com/stsdev

Find Permission and perform action based on Admin access

Find Permission
SPWeb thisweb = SPControl.GetContextWeb(Context);
isAdmin = thisweb.DoesUserHavePermissions(SPBasePermissions.ManageLists);
if (isAdmin == true)
{
// todo
}

Setting URL of link Programatically

SPList list = web.Lists["Links"];

SPListItem newLink = list.Items.Add();

SPFieldUrlValue value = new SPFieldUrlValue();

value.Description = "test";

value.Url = "http://www.microsoft.com/sharepoint";

newLink["URL"] = value;

newLink.Update();

Diaplaying Link field in ItemStyle

< name="LinkList" match="Row[@Style='LinkList']" mode="itemstyle">
< name="DisplayTitle">
< name="OuterTemplate.GetTitle">
< name="Title" select="@URL">
< name="UrlColumnName" select="'URL'">
< /xsl:call-template>
< /xsl:variable>
< name="LinkTarget">
< test="@OpenInNewWindow = 'True'"> _blank< /xsl:if>
< /xsl:variable>
< id="linkitem" class="item">
< class="bullet link-item">
< name="OuterTemplate.CallPresenceStatusIconTemplate">
<>
< name="href">
< select="substring-before($DisplayTitle,', ')">
< /xsl:value-of>
< /xsl:attribute>
< name="title">
< select="@Description">
< /xsl:value-of>
< /xsl:attribute>
< select="substring-after($DisplayTitle,', ')">
< /xsl:value-of>
< /a>
< /div>
< /div>
< /xsl:template>